kbuild arch/i386: make install no longer check vmlinux

make install is often executed as root or on a different mechine via NFS
To avoid updating vmlinux due to directory changes or similar the install target
for i386 no longer has vmlinux as a prerequisite. 
Now modules_install and install are aligned in this respect.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

arch/i386/Makefile

@@ -137,7 +137,10 @@ zlilo bzlilo: vmlinux
 zdisk bzdisk: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) BOOTIMAGE=$(KBUILD_IMAGE) zdisk
 
-install fdimage fdimage144 fdimage288: vmlinux
+fdimage fdimage144 fdimage288: vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) BOOTIMAGE=$(KBUILD_IMAGE) $@
+
+install:
 	$(Q)$(MAKE) $(build)=$(boot) BOOTIMAGE=$(KBUILD_IMAGE) $@
 
 prepare: include/asm-$(ARCH)/asm_offsets.h