mtd: remove mtd_probe() function

The device_probe() function does the same thing as mtd_probe() and
mtd_probe() is only used in mtd_probe_uclass_mtd_devs(), where the
probing can be made simpler by using uclass_foreach_dev_probe macro.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Cc: Priyanka Jain <priyanka.jain@nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Heiko Schocher <hs@denx.de>
Cc: Patrick Delaunay <patrick.delaunay@st.com>

include/mtd.h

@@ -8,7 +8,6 @@
 
 #include <linux/mtd/mtd.h>
 
-int mtd_probe(struct udevice *dev);
 int mtd_probe_devices(void);
 
 void board_mtdparts_default(const char **mtdids, const char **mtdparts);