qemu: fix regression for ppc64

qemu: fix regression for ppc64

The qemu upstream commit, fcac98d0 (linux-user: Remove ELF_HWCAP2),
accidently introduced a regression. It used get_elf_hwcap where
get_elf_hwcap2 should be used.

With recent qemu upgrade in Yocto (10.1.3 -> 10.2.0), qemuppc64 build
is basically broken. There are a lot of do_configure failures with error
message like below:

  Fatal glibc error: CPU lacks ISA 3.00 support (POWER9 or later required)

Backport a patch to fix this issue.

Note that although the problem was only revealed for qemuppc64, some arm
and arm64 machines will also likely get the same issue, as in qemu source
we have:
  linux-user/aarch64/target_elf.h:#define HAVE_ELF_HWCAP2         1
  linux-user/arm/target_elf.h:#define HAVE_ELF_HWCAP2         1
  linux-user/ppc/target_elf.h:#define HAVE_ELF_HWCAP2         1

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>