sparc: vdso: clean-up vdso Makefile

arch/sparc/vdso/Makefile is a replica of arch/x86/entry/vdso/Makefile.

Clean-up the Makefile in the same way as I did for x86:

 - Remove unnecessary export
 - Put the generated linker script to $(obj)/ instead of $(src)/
 - Simplify cmd_vdso2c

The corresponding x86 commits are:

 - 61615faf ("x86/build/vdso: Remove unnecessary export in Makefile")
 - 1742ed20 ("x86/build/vdso: Put generated linker scripts to $(obj)/")
 - c5fcdbf1 ("x86/build/vdso: Simplify 'cmd_vdso2c'")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/vdso/Makefile

@@ -31,23 +31,21 @@ obj-y += $(vdso_img_objs)
 targets += $(vdso_img_cfiles)
 targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
 
-export CPPFLAGS_vdso.lds += -P -C
+CPPFLAGS_vdso.lds += -P -C
 
 VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
 			-Wl,--no-undefined \
 			-Wl,-z,max-page-size=8192 -Wl,-z,common-page-size=8192 \
 			$(DISABLE_LTO)
 
-$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
+$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
 	$(call if_changed,vdso)
 
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include
 hostprogs-y			+= vdso2c
 
 quiet_cmd_vdso2c = VDSO2C  $@
-define cmd_vdso2c
-	$(obj)/vdso2c $< $(<:%.dbg=%) $@
-endef
+      cmd_vdso2c = $(obj)/vdso2c $< $(<:%.dbg=%) $@
 
 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
 	$(call if_changed,vdso2c)