KVM: MMU: split reset_rsvds_bits_mask
KVM: MMU: split reset_rsvds_bits_mask

Since softmmu & AMD nested shadow page tables and guest page tables have
the same format, split reset_rsvds_bits_mask so that the logic can be
reused by later patches which check zero bits on sptes

Signed-off-by: Xiao Guangrong <6fc2b53ba6812a2fb8db97f50bf4ccdfcb5efe9c@linux.intel.com>
Signed-off-by: Paolo Bonzini <69d3ebcf5ee4e7f05a50dc23cd96655b730804b4@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs