alpha: merge build rules of division routines

These four objects are generated by the same build rule, with
different compile options.  The build rules can be merged.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/alpha/lib/Makefile b/arch/alpha/lib/Makefile
index 7b694fe..5f12e9d 100644
--- a/arch/alpha/lib/Makefile
+++ b/arch/alpha/lib/Makefile
@@ -46,11 +46,6 @@
 AFLAGS___divlu.o = -DDIV       -DINTSIZE
 AFLAGS___remlu.o =       -DREM -DINTSIZE
 
-$(obj)/__divqu.o: $(src)/$(ev6-y)divide.S
-	$(cmd_as_o_S)
-$(obj)/__remqu.o: $(src)/$(ev6-y)divide.S
-	$(cmd_as_o_S)
-$(obj)/__divlu.o: $(src)/$(ev6-y)divide.S
-	$(cmd_as_o_S)
-$(obj)/__remlu.o: $(src)/$(ev6-y)divide.S
+$(addprefix $(obj)/,__divqu.o __remqu.o __divlu.o __remlu.o): \
+							$(src)/$(ev6-y)divide.S
 	$(cmd_as_o_S)