x86/virt: Drop unnecessary check on extended CPUID level in cpu_has_svm()

[ Upstream commit 5df8ecfe3632d5879d1f154f7aa8de441b5d1c89 ]

Drop the explicit check on the extended CPUID level in cpu_has_svm(), the
kernel's cached CPUID info will leave the entire SVM leaf unset if said
leaf is not supported by hardware.  Prior to using cached information,
the check was needed to avoid false positives due to Intel's rather crazy
CPUID behavior of returning the values of the maximum supported leaf if
the specified leaf is unsupported.

Fixes: 682a8108 ("x86/kvm/svm: Simplify cpu_has_svm()")
Link: https://lore.kernel.org/r/20230721201859.2307736-13-seanjc@google.com


Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>