KVM: selftests: Fix reserved value WRMSR testcase for multi-feature MSRs

KVM: selftests: Fix reserved value WRMSR testcase for multi-feature MSRs

When determining whether or not a WRMSR with reserved bits will #GP or
succeed due to the WRMSR not existing per the guest virtual CPU model,
expect failure if and only if _all_ features associated with the MSR are
unsupported.  Checking only the primary feature results in false failures
when running on AMD and Hygon CPUs with only one of RDPID or RDTSCP, as
AMD/Hygon CPUs ignore MSR_TSC_AUX[63:32], i.e. don't treat the bits as
reserved, and so #GP only if the MSR is unsupported.

Fixes: 9c38ddb3df94 ("KVM: selftests: Add an MSR test to exercise guest/host and read/write")
Reported-by: Zhiquan Li <zhiquan_li@163.com>
Closes: https://lore.kernel.org/all/20260209041305.64906-6-zhiquan_li@163.com
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260212103841.171459-5-zhiquan_li@163.com
Signed-off-by: Sean Christopherson <seanjc@google.com>