UPSTREAM: mmc-utils: Add disable partition boot to 'mmc bootpart enable'

Modified 'bootpart enable' function to disable partition boot
by setting the <partition> parameter to 0.

BUG=None
TEST=Compile

Signed-off-by: Markus Schuetterle <markus.schuetterle@intel.com>
Signed-off-by: Chris Ball <chris@printf.net>
(cherry picked from commit bb779acfc385d135b32a6998c1d1fceef0491400)
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>

Change-Id: I9c720f2bfa79db36cd0f4d6d921bce08c1668d84
Reviewed-on: https://chromium-review.googlesource.com/1114438
Commit-Ready: Gwendal Grignou <gwendal@chromium.org>
Tested-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
diff --git a/mmc_cmds.c b/mmc_cmds.c
index 797b572..2bc78d4 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -286,6 +286,9 @@
 	value = ext_csd[EXT_CSD_PART_CONFIG];
 
 	switch (boot_area) {
+	case EXT_CSD_PART_CONFIG_ACC_NONE:
+		value &= ~(7 << 3);
+		break;
 	case EXT_CSD_PART_CONFIG_ACC_BOOT0:
 		value |= (1 << 3);
 		value &= ~(3 << 4);