Check alignment of 'src' pointer in optimized ARM routines

fbCompositeSrcAdd_8000x8000arm() tries to align 'dst' already but must check
'src' too.  Else, the next 4-byte copy loop might access odd 'src' address
causing an alignment trap.

Index: pixman-0.12.0/pixman/pixman-arm.c
===================================================================
--- pixman-0.12.0.orig/pixman/pixman-arm.c
+++ pixman-0.12.0/pixman/pixman-arm.c
@@ -60,7 +60,7 @@ fbCompositeSrcAdd_8000x8000arm (pixman_o
 	srcLine += srcStride;
 	w = width;
 
-	while (w && (unsigned long)dst & 3)
+	while (w && (((unsigned long)dst & 3) || ((unsigned long)src & 3)))
 	{
 	    s = *src;
 	    d = *dst;