reboot-mode: Add NVMEM reboot mode

This adds an NVMEM reboot mode driver, similar to Linux's
implementation. This allows using the same device tree binding for Linux
and U-Boot in most cases.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 237f394..b2de50c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1198,6 +1198,7 @@
 S:	Maintained
 F:	doc/api/nvmem.rst
 F:	drivers/misc/nvmem.c
+F:	drivers/reboot-mode/reboot-mode-nvmem.c
 F:	include/nvmem.h
 
 NXP C45 TJA11XX PHY DRIVER