KVM: SVM: Return -EINVAL instead of MSR_INVALID to signal out-of-range MSR

KVM: SVM: Return -EINVAL instead of MSR_INVALID to signal out-of-range MSR

Return -EINVAL instead of MSR_INVALID from svm_msrpm_bit_nr() to indicate
that the MSR isn't covered by one of the (currently) three MSRPM ranges,
and delete the MSR_INVALID macro now that all users are gone.

Link: https://lore.kernel.org/r/20250610225737.156318-29-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>