Fix typo in -masm-dialect option values.

2017-02-21  Martin Liska  <mliska@suse.cz>

	* config/i386/i386.opt: Replace -masm-dialect with -masm.

From-SVN: r245624

gcc/ChangeLog

+2017-02-21  Martin Liska  <mliska@suse.cz>
+
+	* config/i386/i386.opt: Replace -masm-dialect with -masm.
+
 2017-02-21  Thomas Schwinge  <thomas@codesourcery.com>
 
 	PR translation/79638

gcc/config/i386/i386.opt

@@ -258,7 +258,7 @@ Use given assembler dialect.
 
 Enum
 Name(asm_dialect) Type(enum asm_dialect)
-Known assembler dialects (for use with the -masm-dialect= option):
+Known assembler dialects (for use with the -masm= option):
 
 EnumValue
 Enum(asm_dialect) String(intel) Value(ASM_INTEL)