watchdog: remove old STMP3xxx driver

Now that the new driver is in place, we can remove the old one.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --cc drivers/watchdog/Kconfig
Simple merge

diff --cc drivers/watchdog/Makefile
Simple merge

diff --cc drivers/watchdog/stmp3xxx_wdt.c
Simple merge