x86: slightly correct / simplify *vec_extractv2ti

V2TImode values cannot appear in the upper 16 YMM registers without
AVX512VL being enabled. Therefore forcing 512-bit mode (also not
reflected in the "mode" attribute) is pointless.

gcc/

	* config/i386/sse.md (*vec_extractv2ti): Drop g modifiers.

Author: jbeulich

gcc/config/i386/sse.md

@@ -20115,7 +20115,7 @@
   "TARGET_AVX"
   "@
    vextract%~128\t{%2, %1, %0|%0, %1, %2}
-   vextracti32x4\t{%2, %g1, %0|%0, %g1, %2}"
+   vextracti32x4\t{%2, %1, %0|%0, %1, %2}"
   [(set_attr "type" "sselog")
    (set_attr "prefix_extra" "1")
    (set_attr "length_immediate" "1")