unix: fix vet warnings on solaris

Fixes golang/go#17252.

Change-Id: I244c14d531542ea154f82e402059f4bc999241e2
Reviewed-on: https://go-review.googlesource.com/43211
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

unix/asm_solaris_amd64.s

@@ -10,8 +10,8 @@
 // System calls for amd64, Solaris are implemented in runtime/syscall_solaris.go
 //
 
-TEXT ·sysvicall6(SB),NOSPLIT,$0-64
+TEXT ·sysvicall6(SB),NOSPLIT,$0-88
 	JMP	syscall·sysvicall6(SB)
 
-TEXT ·rawSysvicall6(SB),NOSPLIT,$0-64
+TEXT ·rawSysvicall6(SB),NOSPLIT,$0-88
 	JMP	syscall·rawSysvicall6(SB)