fixed #4 csrot & drot returned the wrong result when incx==incy==0 on i686 arch.

kernel/x86/rot_sse2.S

@@ -859,6 +859,10 @@
 
 .L50:
 	movl	N,  I
+	cmpl	$0, INCX
+	je  .L56
+	cmpl	$0, INCY
+	je  .L56
 	sarl	$2, I
 	jle	.L55
 	ALIGN_3

kernel/x86/zrot_sse.S

@@ -1285,6 +1285,12 @@
 
 .L50:
 	movl	N,  I
+//if incx ==0 || incy==0 jump to the tail	
+	cmpl	$0, INCX
+	je  .L56
+	cmpl	$0, INCY
+	je  .L56
+	
 	sarl	$2, I
 	jle	.L55
 	ALIGN_3