powerpc: Sync hwcap.h with kernel

Linux commit b4b56f9ecab40f3b4ef53e130c9f6663be491894 introduced
a new HWCAP2 bit to indicate that the kernel now aborts a memory
transaction when a syscall is made.  This patch adds that bit to
sysdeps/powerpc/bits/hwcap.h.

	* sysdeps/powerpc/bits/hwcap.h: Add PPC_FEATURE2_HTM_NOSC.
	* sysdeps/powerpc/dl-procinfo.c:
	(_dl_powerpc_cap_flags): Added descriptor for this hwcap
	feature so it shows when LD_SHOW_AUXV=1.

(cherry picked from commit 3c13f28c)