[AArch64][BZ 18400] fix elf_prpsinfo in procfs.h

[AArch64][BZ 18400] fix elf_prpsinfo in procfs.h

Kernel uses int pr_uid, pr_gid, but glibc used unsigned short.

This is an ABI breaking change, but the size and alignment of
the struct and the layout of other members is not changed and
there is no known usage of pr_uid and pr_gid so it is expected
to be safe.

	[BZ #18400]
	* sysdeps/unix/sysv/linux/aarch64/sys/procfs.h (struct elf_prpsinfo):
	Fix pr_uid and pr_gid members.