powerpc/kvm: Fall through switch case explicitly

Implicit fallthrough warning was enabled globally which broke
the build. Make it explicit with a `fall through` comment.

Signed-off-by: Santosh Sivaraj <[email protected]>
Reviewed-by: Stephen Rothwell <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: santoshs

arch/powerpc/kvm/book3s_32_mmu.c

@@ -239,6 +239,7 @@ static int kvmppc_mmu_book3s_32_xlate_pte(struct kvm_vcpu *vcpu, gva_t eaddr,
 				case 2:
 				case 6:
 					pte->may_write = true;
+					/* fall through */
 				case 3:
 				case 5:
 				case 7: