x86/hyperv: use helpers to read control registers in hv_snp_boot_ap()

Use native_read_cr*() helpers to read control registers into vmsa->cr*
instead of open-coded assembly.

No functional change intended, unless there was a purpose to specifying
rax.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Link: https://lore.kernel.org/r/20240805201247.427982-1-yosryahmed@google.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240805201247.427982-1-yosryahmed@google.com>