x86, build: Do not set the root_dev field in bzImage

This has been obsoleted by the root= commandline and the rdev utility
for many, many years.  People who still depend on this will surely
have a copy of the rdev utility around, the rest of the world gets rid
of another piece of buildhost-dependent data in the build. Thanks to
Paul Bolle for the build.c cleanup.

Cc: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Link: http://lkml.kernel.org/r/1302607824-24699-1-git-send-email-mmarek@suse.cz
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index f7cb086..95365a8 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -9,12 +9,6 @@
 # Changed by many, many contributors over the years.
 #
 
-# ROOT_DEV specifies the default root-device when making the image.
-# This can be either FLOPPY, CURRENT, /dev/xxxx or empty, in which case
-# the default of FLOPPY is used by 'build'.
-
-ROOT_DEV	:= CURRENT
-
 # If you want to preset the SVGA mode, uncomment the next line and
 # set SVGA_MODE to whatever number you want.
 # Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
@@ -75,8 +69,7 @@
 $(obj)/bzImage: asflags-y  := $(SVGA_MODE)
 
 quiet_cmd_image = BUILD   $@
-cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin \
-	$(ROOT_DEV) > $@
+cmd_image = $(obj)/tools/build $(obj)/setup.bin $(obj)/vmlinux.bin > $@
 
 $(obj)/bzImage: $(obj)/setup.bin $(obj)/vmlinux.bin $(obj)/tools/build FORCE
 	$(call if_changed,image)