[klibc] alpha: fix pipe() system call

Fix setting the return value for the pipe() system call.  I managed
to forget that Alpha syntax is backwards compared to MIPS.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/usr/klibc/arch/alpha/pipe.S b/usr/klibc/arch/alpha/pipe.S
index 18244db..ee72413 100644
--- a/usr/klibc/arch/alpha/pipe.S
+++ b/usr/klibc/arch/alpha/pipe.S
@@ -30,9 +30,9 @@
 	ret	zero,(ra),1
 1:
 	stl	v0, 0(a0)
-	mov	v0, zero
-	stl	a3, 4(a0)
+	lda	v0, 0
+	stl	a4, 4(a0)
 	ret	zero,(ra),1
 
-	.size	__syscall_dual1,.-__syscall_dual1
-	.end	__syscall_dual1
+	.size	pipe,.-pipe
+	.end	pipe