rename sys functions to runtime,
because they are in package runtime.

another step to enforcing package boundaries.

R=r
DELTA=732  (114 added, 93 deleted, 525 changed)
OCL=35811
CL=35824
diff --git a/src/pkg/runtime/linux/arm/sys.s b/src/pkg/runtime/linux/arm/sys.s
index d7eb43e..4eb38f1 100644
--- a/src/pkg/runtime/linux/arm/sys.s
+++ b/src/pkg/runtime/linux/arm/sys.s
@@ -22,7 +22,7 @@
 	// Exit value already in R0
 	SWI	$SYS_exit
 
-TEXT sys·mmap(SB),7,$0
+TEXT runtime·mmap(SB),7,$0
 	MOVW	0(FP), R0
 	MOVW	4(FP), R1
 	MOVW	8(FP), R2