configure: move arm arch extensions to a separate variable

Signed-off-by: Mans Rullgard <mans@mansr.com>

configure

@@ -1096,6 +1096,15 @@ ARCH_LIST='
     x86_64
 '
 
+ARCH_EXT_LIST_ARM='
+    armv5te
+    armv6
+    armv6t2
+    armvfp
+    neon
+    vfpv3
+'
+
 ARCH_EXT_LIST_X86='
     amd3dnow
     amd3dnowext
@@ -1112,15 +1121,10 @@ ARCH_EXT_LIST_X86='
 '
 
 ARCH_EXT_LIST="
+    $ARCH_EXT_LIST_ARM
     $ARCH_EXT_LIST_X86
     altivec
-    armv5te
-    armv6
-    armv6t2
-    armvfp
-    neon
     ppc4xx
-    vfpv3
     vis
 "