KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.h

nvhe/mem_protect.h refers to __load_stage2() in the definition of
__load_host_stage2() but doesn't include the relevant header.

Include asm/kvm_mmu.h in nvhe/mem_protect.h so that users of the latter
don't have to do this themselves.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-10-will@kernel.org

arch/arm64/kvm/hyp/include/nvhe/mem_protect.h

@@ -8,6 +8,7 @@
 #define __KVM_NVHE_MEM_PROTECT__
 #include <linux/kvm_host.h>
 #include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
 #include <asm/virt.h>
 #include <nvhe/spinlock.h>