gen_initramfs_list.sh: fix 'bad variable name' error

Prior to commit 858805b336 ("kbuild: add $(BASH) to run scripts with
bash-extension"), this shell script was almost always run by bash since
bash is usually installed on the system by default.

Now, this script is run by sh, which might be a symlink to dash. On such
distributions, the following code emits an error:

  local dev=`LC_ALL=C ls -l "${location}"`

You can reproduce the build error, for example by setting
CONFIG_INITRAMFS_SOURCE="/dev".

    GEN     usr/initramfs_data.cpio.gz
  ./usr/gen_initramfs_list.sh: 131: local: 1: bad variable name
  make[1]: *** [usr/Makefile:61: usr/initramfs_data.cpio.gz] Error 2

This is because `LC_ALL=C ls -l "${location}"` contains spaces.
Surrounding it with double-quotes fixes the error.

Fixes: 858805b336 ("kbuild: add $(BASH) to run scripts with bash-extension")
Reported-by: Jory A. Pratt <anarchy@gentoo.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

usr/gen_initramfs_list.sh

@@ -128,7 +128,7 @@ parse() {
 			str="${ftype} ${name} ${location} ${str}"
 			;;
 		"nod")
-			local dev=`LC_ALL=C ls -l "${location}"`
+			local dev="`LC_ALL=C ls -l "${location}"`"
 			local maj=`field 5 ${dev}`
 			local min=`field 6 ${dev}`
 			maj=${maj%,}