MXS specific devices have some common infrastructure in the kernel
known as STMP devices. We have the same in barebox, but with a
mxs_ prefix instead of a stmp_ prefix. As some STMP devices are
also found on i.MX6 move the common infrastructure out of MXS
specific files and use the stmp_ prefix.

This is done in preparation for i.MX6 NAND support.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Needed for ocotp write.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

usbphy initializaion needs to access the power supply and has this
embedded. Refactor to a seperate power.c, since we need other accesses
in the future.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>