KVM: x86: Return bool instead of int for CR4 and SREGS validity checks

mainline inclusion
from mainline-v5.11-rc1
commit ee69c92b
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I7S3VQ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ee69c92bac61f4379e97f40b259a1c1257e5987f



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Rework the common CR4 and SREGS checks to return a bool instead of an
int, i.e. true/false instead of 0/-EINVAL, and add "is" to the name to
clarify the polarity of the return value (which is effectively inverted
by this change).

No functional changed intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20201007014417.29276-6-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

conflict:
	arch/x86/kvm/x86.c

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>