RISC-V: The version of i-ext should be RISCV_UNKNOWN_VERSION when expanding g-ext.

Fix the wrong version of i-ext when expanding g-ext.  This was changed by
the previous patch accidently.

bfd/
    * elfxx-riscv.c (riscv_parse_std_ext): Fixed the wrong versions of
    i-ext when expanding g-ext.

bfd/ChangeLog

@@ -1,3 +1,8 @@
+2021-04-12  Nelson Chu  <nelson.chu@sifive.com>
+
+	* elfxx-riscv.c (riscv_parse_std_ext): Fixed the wrong versions of
+	i-ext when expanding g-ext.
+
 2021-04-12  Nelson Chu  <nelson.chu@sifive.com>
 
 	* elfxx-riscv.c (riscv_ext_dont_care_version): Removed.

bfd/elfxx-riscv.c

@@ -1514,8 +1514,8 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
 					  &minor_version, true);
 	/* Expand g to imafd.  */
 	riscv_parse_add_subset (rps, "i",
-				major_version,
-				minor_version, false);
+				RISCV_UNKNOWN_VERSION,
+				RISCV_UNKNOWN_VERSION, false);
 	for ( ; *std_exts != 'q'; std_exts++)
 	  {
 	    subset[0] = *std_exts;