KVM: Declare kvm_arch_flush_remote_tlbs() globally

There's no reason for the architectures to declare
kvm_arch_flush_remote_tlbs() in their own headers. Hence to
avoid this duplication, make the declaration global, leaving
the architectures to define only __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
as needed.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230811045127.3308641-3-rananta@google.com

arch/mips/include/asm/kvm_host.h

@@ -897,6 +897,5 @@ static inline void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) {}
 
 #define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
-int kvm_arch_flush_remote_tlbs(struct kvm *kvm);
 
 #endif /* __MIPS_KVM_HOST_H__ */

include/linux/kvm_host.h

@@ -1484,6 +1484,8 @@ static inline int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
 {
 	return -ENOTSUPP;
 }
+#else
+int kvm_arch_flush_remote_tlbs(struct kvm *kvm);
 #endif
 
 #ifdef __KVM_HAVE_ARCH_NONCOHERENT_DMA