Some of the i.MXs drivers can be build tested even if building for other
platforms. Support adding a future COMPILE_TEST dependency to some of
these drivers by explicitly having their Kconfig symbol select STMP_DEVICE
if the driver calls stmp_reset_block.

This has not been necessary for the normal build, because the ARCH
symbols for the IMX23 and IMX28 already selected STMP_DEVICE.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>