all: fix assembly vet issues

Add missing function prototypes.
Fix function prototypes.
Use FP references instead of SP references.
Fix variable names.
Update comments.
Clean up whitespace. (Not for vet.)

All fairly minor fixes to make vet happy.

Updates #11041

Change-Id: Ifab2cdf235ff61cdc226ab1d84b8467b5ac9446c
Reviewed-on: https://go-review.googlesource.com/27713
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/syscall/asm_openbsd_arm.s b/src/syscall/asm_openbsd_arm.s
index 4f034a0..9279ed9 100644
--- a/src/syscall/asm_openbsd_arm.s
+++ b/src/syscall/asm_openbsd_arm.s
@@ -17,7 +17,7 @@
 
 TEXT	·Syscall(SB),NOSPLIT,$0-28
 	BL runtime·entersyscall(SB)
-	MOVW syscall+0(FP), R12		// syscall number
+	MOVW trap+0(FP), R12		// syscall number
 	MOVW a1+4(FP), R0		// arg 1
 	MOVW a2+8(FP), R1		// arg 2
 	MOVW a3+12(FP), R2		// arg 3
@@ -39,7 +39,7 @@
 
 TEXT	·Syscall6(SB),NOSPLIT,$0-40
 	BL runtime·entersyscall(SB)
-	MOVW syscall+0(FP), R12		// syscall number
+	MOVW trap+0(FP), R12		// syscall number
 	MOVW a1+4(FP), R0		// arg 1
 	MOVW a2+8(FP), R1		// arg 2
 	MOVW a3+12(FP), R2		// arg 3
@@ -65,7 +65,7 @@
 
 TEXT	·Syscall9(SB),NOSPLIT,$0-52
 	BL runtime·entersyscall(SB)
-	MOVW syscall+0(FP), R12		// syscall number
+	MOVW num+0(FP), R12		// syscall number
 	MOVW a1+4(FP), R0		// arg 1
 	MOVW a2+8(FP), R1		// arg 2
 	MOVW a3+12(FP), R2		// arg 3
@@ -90,7 +90,7 @@
 	RET
 
 TEXT	·RawSyscall(SB),NOSPLIT,$0-28
-	MOVW syscall+0(FP), R12		// syscall number
+	MOVW trap+0(FP), R12		// syscall number
 	MOVW a1+4(FP), R0		// arg 1
 	MOVW a2+8(FP), R1		// arg 2
 	MOVW a3+12(FP), R2		// arg 3
@@ -109,7 +109,7 @@
 	RET
 
 TEXT	·RawSyscall6(SB),NOSPLIT,$0-40
-	MOVW syscall+0(FP), R12		// syscall number
+	MOVW trap+0(FP), R12		// syscall number
 	MOVW a1+4(FP), R0		// arg 1
 	MOVW a2+8(FP), R1		// arg 2
 	MOVW a3+12(FP), R2		// arg 3