Correct __ASSUME_PRLIMIT64 for hppa/microblaze/sh (bug 17779).

Correct __ASSUME_PRLIMIT64 for hppa/microblaze/sh (bug 17779).

__ASSUME_PRLIMIT64 is defined in kernel-features.h for kernels 2.6.36
and later, but hppa, microblaze and sh did not add the prlimit64
syscall until 2.6.37.  This patch adds corresponding undefines of
__ASSUME_PRLIMIT64 to those architectures' kernel-features.h files.

(This concludes the kernel-features.h fixes arising out of the review
- limited to macros defined in the architecture-independent
kernel-features.h file - I did in connection with the move to 2.6.32
minimum kernel version.  For that subset of macros - I didn't check
any purely architecture-specific macros - I think they are now defined
for the correct kernel versions on each architecture after this
patch.)

	[BZ #17779]
	* sysdeps/unix/sysv/linux/hppa/kernel-features.h
	[__LINUX_KERNEL_VERSION < 0x020625] (__ASSUME_PRLIMIT64):
	Undefine.
	* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
	[__LINUX_KERNEL_VERSION < 0x020625] (__ASSUME_PRLIMIT64):
	Likewise.
	* sysdeps/unix/sysv/linux/sh/kernel-features.h
	[__LINUX_KERNEL_VERSION < 0x020625] (__ASSUME_PRLIMIT64):
	Likewise.