MAINTAINERS: add tambarus as reviewer for SPI NOR

I'd like to get Cc'ed to u-boot's SPI NOR patches to help review them.
The ultimate goal is to have an aligned approach in u-boot and linux.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 38c714c..df04619 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1604,6 +1604,7 @@
 SPI-NOR
 M:	Jagan Teki <jagan@amarulasolutions.com>
 M:	Vignesh R <vigneshr@ti.com>
+R:	Tudor Ambarus <tudor.ambarus@linaro.org>
 S:	Maintained
 F:	drivers/mtd/spi/
 F:	include/spi_flash.h