target/ppc: combine multiple ail checks into one

ppc_excp_apply_ail has multiple if-checks for ail which is un-necessary.
Combine them as appropriate.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index 2806afd..70daa50 100644
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -324,10 +324,7 @@
         }
 
         ail = (env->spr[SPR_LPCR] & LPCR_AIL) >> LPCR_AIL_SHIFT;
-        if (ail == 0) {
-            return;
-        }
-        if (ail == 1) {
+        if (ail == 0 || ail == 1) {
             /* AIL=1 is reserved, treat it like AIL=0 */
             return;
         }
@@ -351,10 +348,7 @@
         } else {
             ail = (env->spr[SPR_LPCR] & LPCR_AIL) >> LPCR_AIL_SHIFT;
         }
-        if (ail == 0) {
-            return;
-        }
-        if (ail == 1 || ail == 2) {
+        if (ail == 0 || ail == 1 || ail == 2) {
             /* AIL=1 and AIL=2 are reserved, treat them like AIL=0 */
             return;
         }