liblink: fix Plan 9 warnings
warning: src/liblink/asm5.c:485 non-interruptable temporary
warning: src/liblink/asm5.c:565 set and not used: c
warning: src/liblink/asm5.c:622 format mismatch ux VLONG, arg 2
warning: src/liblink/asm5.c:1218 overspecified class: asmout GLOBL STATIC
warning: src/liblink/asm5.c:2088 overspecified class: oprrr GLOBL STATIC
warning: src/liblink/asm5.c:2202 overspecified class: opbra GLOBL STATIC
warning: src/liblink/asm5.c:2237 overspecified class: olr GLOBL STATIC
warning: src/liblink/asm5.c:2266 overspecified class: olhr GLOBL STATIC
warning: src/liblink/asm5.c:2291 overspecified class: osr GLOBL STATIC
warning: src/liblink/asm5.c:2302 overspecified class: oshr GLOBL STATIC
warning: src/liblink/asm5.c:2312 overspecified class: osrr GLOBL STATIC
warning: src/liblink/asm5.c:2319 overspecified class: oshrr GLOBL STATIC
warning: src/liblink/asm5.c:2325 overspecified class: olrr GLOBL STATIC
warning: src/liblink/asm5.c:2332 overspecified class: olhrr GLOBL STATIC
warning: src/liblink/asm5.c:2338 overspecified class: ofsr GLOBL STATIC
warning: src/liblink/asm5.c:2375 overspecified class: omvl GLOBL STATIC
warning: src/liblink/asm8.c:1261 format mismatch d VLONG, arg 3
warning: src/liblink/asm8.c:1274 format mismatch +d VLONG, arg 5
warning: src/liblink/list5.c:153 format mismatch d VLONG, arg 3
warning: src/liblink/list5.c:310 format mismatch d VLONG, arg 3
warning: src/liblink/obj6.c:665 set and not used: q
warning: src/liblink/pcln.c:32 set and not used: p
R=golang-dev, jas, gobot, rsc
CC=golang-dev
https://golang.org/cl/
40370043