[PATCH] reduce casting in sysenter.c

[PATCH] reduce casting in sysenter.c

Ran across this because it's another place where an unsigned long is passed
directly to __pa().  Making the "page" variable a void* seems a bit more
natural than an unsigned long and reduces the net number of casts by 1.
Without it, we probably need another (void *) cast in the __pa() call.

For more explanation as to why this was probably done originally, see this
post: http://marc.theaimsgroup.com/?l=linux-mm&m=109155379124628&w=2

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>