factor out Ep3 USA check in patches

system/ppc/Ep3-Editors.patch.s

@@ -22,6 +22,8 @@ start:
   # But we leave it in to be consistent with patches for Episodes 1&2.
   .include InitClearCaches
 
+  .include Episode3USAOnly
+
   stwu   [r1 - 0x20], r1
   mflr   r0
   stw    [r1 + 0x24], r0
@@ -29,15 +31,6 @@ start:
   stw    [r1 + 0x0C], r30
   stw    [r1 + 0x08], r29
 
-  # First, make sure this is actually Episode 3 USA; if not, do nothing
-  lis    r4, 0x4750
-  ori    r4, r4, 0x5345 # 'GPSE'
-  lis    r5, 0x8000
-  lwz    r5, [r5]
-  li     r3, -1
-  cmp    r4, r5
-  bne    skip_all
-
   # Write a short hook that updates our editors table when TEditor_destroy() is
   # called
   bl     get_TEditor_destroy_hook_addr

system/ppc/Ep3-VIPCard.patch.s

@@ -15,14 +15,7 @@ start:
   # But we leave it in to be consistent with patches for Episodes 1&2.
   .include InitClearCaches
 
-  # First, make sure this is actually Episode 3 USA; if not, do nothing
+  .include Episode3USAOnly
-  lis    r4, 0x4750
-  ori    r4, r4, 0x5345 # 'GPSE'
-  lis    r5, 0x8000
-  lwz    r5, [r5]
-  li     r3, -1
-  cmp    r4, r5
-  bnelr
 
   # Call seq_var_set(7000) - this gives the local player a VIP card
   li     r3, 7000

system/ppc/Episode3USAOnly.inc.s

@@ -0,0 +1,7 @@
+  lis    r4, 0x4750
+  ori    r4, r4, 0x5345 # 'GPSE'
+  lis    r5, 0x8000
+  lwz    r5, [r5]
+  li     r3, -1
+  cmp    r4, r5
+  bnelr