x86: fix "make install" target

Removing the dependency on the boot image build was good, but it also
meant that the $< expansion by make needed to be done explicitly.

Noted by Stephen Hemminger.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/boot/Makefile

@@ -101,4 +101,4 @@ zlilo: $(BOOTIMAGE)
 	if [ -x /sbin/lilo ]; then /sbin/lilo; else /etc/lilo/install; fi
 
 install:
-	sh $(srctree)/$(src)/install.sh $(KERNELRELEASE) $< System.map "$(INSTALL_PATH)"
+	sh $(srctree)/$(src)/install.sh $(KERNELRELEASE) $(BOOTIMAGE) System.map "$(INSTALL_PATH)"