correct TARGET_ADDR_SPACE_SUBSET_P documentation.

Hi, 
I notice the following description is different from how spu & m32c use it. 

In internal manual:

bool TARGET_ADDR_SPACE_SUBSET_P (addr space t superset, [Target Hook]
addr space t subset)
Define this to return whether the subset named address space is contained within the
superset named address space. Pointers to a named address space that is a subset
of another named address space will be converted automatically without a cast if
used together in arithmetic operations. Pointers to a superset address space can be
converted to pointers to a subset address space via explicit casts.

In spu & m32c ports:
m32c_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
spu_addr_space_subset_p (addr_space_t subset, addr_space_t superset)

I believe the document is wrong. The first argument is subset and the second
one is superset. I attached the patch below. OK for trunk?


Cheers,
Bingfeng Mei

2011-09-26  Bingfeng Mei <bmei@broad.com>
	* doc/tm.texi: Correct documentation for TARGET_ADDR_SPACE_SUBSET_P.

On Mon, Sep 26, 2011 at 11:20 AM, Bingfeng Mei <bmei@broadcom.com> wrote:
> Hi,
> I notice the following description is different from how spu & m32c use it.
>
> In internal manual:
>
> bool TARGET_ADDR_SPACE_SUBSET_P (addr space t superset, [Target Hook]
> addr space t subset)
> Define this to return whether the subset named address space is contained within the
> superset named address space. Pointers to a named address space that is a subset
> of another named address space will be converted automatically without a cast if
> used together in arithmetic operations. Pointers to a superset address space can be
> converted to pointers to a subset address space via explicit casts.
>
> In spu & m32c ports:
> m32c_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
> spu_addr_space_subset_p (addr_space_t subset, addr_space_t superset)
>
> I believe the document is wrong. The first argument is subset and the second
> one is superset. I attached the patch below. OK for trunk?

Please also adjust target.def and tm.texi.in.

>
> Cheers,
> Bingfeng Mei
>
> 2011-09-26  Bingfeng Mei <bmei@broad.com>
>        * doc/tm.texi: Correct documentation for TARGET_ADDR_SPACE_SUBSET_P.
>
>
> Index: doc/tm.texi
> ===================================================================
> --- doc/tm.texi (revision 178972)
> +++ doc/tm.texi (working copy)
> @@ -10256,7 +10256,7 @@ hook is the same as the @code{TARGET_LEG
>  except that it includes explicit named address space support.
>  @end deftypefn
>
> -@deftypefn {Target Hook} bool TARGET_ADDR_SPACE_SUBSET_P (addr_space_t @var{superset}, addr_space_t @var{subset})
> +@deftypefn {Target Hook} bool TARGET_ADDR_SPACE_SUBSET_P (addr_space_t @var{subset}, addr_space_t @var{superset})
>  Define this to return whether the @var{subset} named address space is
>  contained within the @var{superset} named address space.  Pointers to
>  a named address space that is a subset of another named address space
>
>