correct fasp for 386.  in translation from amd64, RARG was not replaced
with a FP-relative load.

Reference: /n/atom/patch/applied2013/fasp386
Date: Fri Sep 27 21:15:59 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libc/386/atom.s	Fri Sep 27 21:10:53 2013
+++ /sys/src/libc/386/atom.s	Fri Sep 27 21:10:53 2013
@@ -74,13 +74,9 @@
 	MOVL	$1,AX
 	RET
 
-//TEXT fas64(SB), 1, $-4
-//	MOVL	p+4(FP), BX
-//	LOCK; XCHGQ	BX, (AX)			/*  */
-//	RET
-
 TEXT fas32(SB), 1, $-4
 TEXT fasp(SB), 1, $-4
-	MOVL	p+4(FP), BX
-	LOCK; XCHGL	BX, (AX)			/*  */
+	MOVL	a+0(FP), BX
+	MOVL	p+4(FP), AX
+	LOCK; XCHGL	AX, (BX)			/*  */
 	RET