x86: fix vdso_install breaks user "make install"

I suggest to make the vdso_install step independent as
in following patch.

This solves the issue at ahnd and still gives us the posibility
to install the files should they be needed.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/powerpc/Makefile

@@ -176,7 +176,7 @@ define archhelp
   @echo '  *_defconfig     - Select default config from arch/$(ARCH)/configs'
 endef
 
-install: vdso_install
+install:
 	$(Q)$(MAKE) $(build)=$(boot) install
 
 vdso_install:

arch/x86/Makefile

@@ -229,7 +229,7 @@ zdisk bzdisk: vmlinux
 fdimage fdimage144 fdimage288 isoimage: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) BOOTIMAGE=$(KBUILD_IMAGE) $@
 
-install: vdso_install
+install:
 	$(Q)$(MAKE) $(build)=$(boot) BOOTIMAGE=$(KBUILD_IMAGE) install
 
 PHONY += vdso_install