x86/srso: Move retbleed IBPB check into existing 'has_microcode' code block

Simplify the code flow a bit by moving the retbleed IBPB check into the
existing 'has_microcode' block.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/0a22b86b1f6b07f9046a9ab763fc0e0d1b7a91d4.1693889988.git.jpoimboe@kernel.org

arch/x86/kernel/cpu/bugs.c

@@ -2430,10 +2430,8 @@ static void __init srso_select_mitigation(void)
 			setup_force_cpu_cap(X86_FEATURE_SRSO_NO);
 			return;
 		}
-	}
 
-	if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) {
-		if (has_microcode) {
+		if (retbleed_mitigation == RETBLEED_MITIGATION_IBPB) {
 			srso_mitigation = SRSO_MITIGATION_IBPB;
 			goto out;
 		}