tilegx: Unbreak build

../../gcc/config/tilegx/tilegx.md:4109:1: ambiguous attribute 'n'; could be '1' (via 'I124MODE:n') or '4' (via 'I48MODE:n')
../../gcc/config/tilegx/tilegx.md:4109:1: ambiguous attribute 'n'; could be '1' (via 'I124MODE:n') or '' (via 'I48MODE:n')
../../gcc/config/tilegx/tilegx.md:4109:1: ambiguous attribute 'n'; could be '2' (via 'I124MODE:n') or '4' (via 'I48MODE:n')
../../gcc/config/tilegx/tilegx.md:4109:1: ambiguous attribute 'n'; could be '2' (via 'I124MODE:n') or '' (via 'I48MODE:n')
../../gcc/config/tilegx/tilegx.md:4109:1: ambiguous attribute 'n'; could be '4' (via 'I124MODE:n') or '' (via 'I48MODE:n')

The insn name already uses <I124MODE:n> explicitly, just the preparation
stmts don't, and as it creates a I124MODE lowpart subreg of a word mode
register, <I124MODE:n> seems obviously correct.

2020-05-02  Jakub Jelinek  <jakub@redhat.com>

	* config/tilegx/tilegx.md
	(insn_stnt<I124MODE:n>_add<I48MODE:bitsuffix>): Use <I124MODE:n>
	rather than just <n>.

gcc/ChangeLog

+2020-05-02  Jakub Jelinek  <jakub@redhat.com>
+
+	* config/tilegx/tilegx.md
+	(insn_stnt<I124MODE:n>_add<I48MODE:bitsuffix>): Use <I124MODE:n>
+	rather than just <n>.
+
 2020-04-30  Alexandre Oliva <oliva@adacore.com>
 
 	* doc/sourcebuild.texi (Effective-Target Keywords): Document

gcc/config/tilegx/tilegx.md

@@ -4110,7 +4110,7 @@
   operands[1] = simplify_gen_subreg (<I124MODE:MODE>mode, operands[1],
 				     DImode,
 				     BYTES_BIG_ENDIAN
-				     ? UNITS_PER_WORD - <n> : 0);
+				     ? UNITS_PER_WORD - <I124MODE:n> : 0);
 })
 
 (define_insn "*insn_stnt<I124MODE:n>_add<I48MODE:bitsuffix>"