Fix whitespace in gas listing errors and warnings

gas/
	* listing.c (listing_warning, listing_error): Add space after colon.
	* messages.c (as_warn_internal, as_bad_internal): Use the same
	string as above.
gas/testsuite/
	* gas/d30v/bittest.l: Update for changed whitespace.
	* gas/d30v/serial.l: Likewise.
	* gas/d30v/serial2.l: Likewise.
	* gas/d30v/serial2O.l: Likewise.
	* gas/d30v/warn_oddreg.l: Likewise.
	* gas/i386/inval-equ-2.l: Likewise.
	* gas/i386/mpx-inval-1.l: Likewise.
	* gas/i386/sse-check-error.l: Likewise.
	* gas/i386/x86-64-mpx-inval-1.l: Likewise.
	* gas/i386/x86-64-mpx-inval-2.l: Likewise.
	* gas/i386/x86-64-size-inval-1.l: Likewise.
	* gas/i386/x86-64-sse-check-error.l: Likewise.