Prepare v2018.07-rc1

Signed-off-by: Tom Rini <trini@konsulko.com>

Makefile

@@ -1,9 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0+
 
 VERSION = 2018
-PATCHLEVEL = 05
+PATCHLEVEL = 07
 SUBLEVEL =
-EXTRAVERSION =
+EXTRAVERSION = -rc1
 NAME =
 
 # *DOCUMENTATION*