configure: Move cpunop into ARCH_EXT_LIST_X86

It is a processor feature, so it belongs there.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -1455,6 +1455,7 @@ ARCH_EXT_LIST_X86='
     amd3dnowext
     avx
     avx2
+    cpunop
     fma3
     fma4
     i686
@@ -1550,7 +1551,6 @@ HAVE_LIST="
     clock_gettime
     closesocket
     CommandLineToArgvW
-    cpunop
     CryptGenRandom
     dcbzl
     dev_bktr_ioctl_bt848_h