KVM: MIPS: defer flush to generic MMU notifier code

mainline inclusion
from mainline-v5.13-rc1
commit fe9a5b05
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=fe9a5b055116dff7fcee081abc2def4b14d24c21



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Return 1 from kvm_unmap_hva_range and kvm_set_spte_hva if a flush is
needed, so that the generic code can coalesce the flushes.

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