util/chromeos/crosfirmware.sh: Add /sbin to PATH

On some systems, such as Debian 9.6, `parted` and `debugfs` are located
in /sbin. Adding /sbin to PATH means that this script can work when run
as a regular user.

Change-Id: I151dba467e2b196f13093334273dae8a05865491
Signed-off-by: Tristan Corrick <tristan@corrick.kiwi>
Reviewed-on: https://review.coreboot.org/c/30547
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

util/chromeos/crosfirmware.sh

@@ -19,6 +19,9 @@
 
 #DEBUG=1
 
+# On some systems, `parted` and `debugfs` are located in /sbin.
+export PATH="$PATH:/sbin"
+
 debug()
 {
 	test "$DEBUG" == "1" && echo "$*"