unix: match seek argument size to signature on linux/arm

Follow CL 2810

Change-Id: Ic833681c7abd8973e952aaad40986fd3385c94db
Reviewed-on: https://go-review.googlesource.com/86895
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/asm_linux_arm.s

@@ -35,7 +35,6 @@ TEXT ·SyscallNoError(SB),NOSPLIT,$0-24
 	BL	runtime·exitsyscall(SB)
 	RET
 
-
 TEXT ·RawSyscall(SB),NOSPLIT,$0-28
 	B	syscall·RawSyscall(SB)
 
@@ -53,5 +52,5 @@ TEXT ·RawSyscallNoError(SB),NOSPLIT,$0-24
 	MOVW	R0, r2+20(FP)
 	RET
 
-TEXT ·seek(SB),NOSPLIT,$0-32
+TEXT ·seek(SB),NOSPLIT,$0-28
 	B	syscall·seek(SB)