cmd/link: remove -W option

The -W option has not worked since Go 1.3.  It is not documented.  When
it did work, it generated useful output, but it was for human viewing;
there was no reason to write a script that passes the -W option, so it's
unlikely that anybody is using it today.

Change-Id: I4769f1ffd308a48324a866592eb7fd79a4cdee54
Reviewed-on: https://go-review.googlesource.com/15701Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/link/internal/ld/pobj.go

@@ -83,7 +83,6 @@ func Ldmain() {
 	obj.Flagint32("R", "set address rounding `quantum`", &INITRND)
 	obj.Flagint64("T", "set text segment `address`", &INITTEXT)
 	obj.Flagfn0("V", "print version and exit", doversion)
-	obj.Flagcount("W", "disassemble input", &Debug['W'])
 	obj.Flagfn1("X", "add string value `definition` of the form importpath.name=value", addstrdata1)
 	obj.Flagcount("a", "disassemble output", &Debug['a'])
 	obj.Flagstr("buildid", "record `id` as Go toolchain build id", &buildid)