Handle FreeBSD-specific AT_EHDRFLAGS and AT_HWCAP auxiliary vector types.

Handle FreeBSD-specific AT_EHDRFLAGS and AT_HWCAP auxiliary vector types.

FreeBSD recently added two additional ELF auxiliary vectors.  FreeBSD's
AT_HWCAP uses a different number compared to AT_HWCAP on Linux as the
numerical value was already in use for a different vector on FreeBSD.

include/ChangeLog:

	* elf/common.h (AT_FREEBSD_EHDRFLAGS, AT_FREEBSD_HWCAP): Define.

gdb/ChangeLog:

	* fbsd-tdep.c (fbsd_print_auxv_entry): Handle AT_EHDRFLAGS and
	AT_HWCAP.