cmd/asm: fix (printing of) TEXT flags

With the new unificiation, the flag must be TYPE_CONST to print
properly.

Change-Id: I7cd1c56355724f08cbe9afc6ab7a66904031adc9
Reviewed-on: https://go-review.googlesource.com/6903Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/asm/internal/asm/asm.go

@@ -141,6 +141,7 @@ func (p *Parser) asmText(word string, operands [][]lex.Token) {
 		Lineno: p.histLineNum,
 		From:   nameAddr,
 		From3: obj.Addr{
+			Type:   obj.TYPE_CONST,
 			Offset: flag,
 		},
 		To: obj.Addr{

src/cmd/asm/internal/asm/testdata/386.out

-5 00001 (testdata/386.s:5)	TEXT	foo(SB), $0
+5 00001 (testdata/386.s:5)	TEXT	foo(SB), 0, $0
 8 00002 (testdata/386.s:8)	SETCC	AX
 9 00003 (testdata/386.s:9)	SETCC	foo+4(SB)
 12 00004 (testdata/386.s:12)	DIVB	AX

src/cmd/asm/internal/asm/testdata/amd64.out

-5 00001 (testdata/amd64.s:5)	TEXT	foo(SB), $0
+5 00001 (testdata/amd64.s:5)	TEXT	foo(SB), 0, $0
 8 00002 (testdata/amd64.s:8)	NEGQ	R11
 9 00003 (testdata/amd64.s:9)	NEGQ	4(R11)
 10 00004 (testdata/amd64.s:10)	NEGQ	foo+4(SB)