putting an error pointer into strerror can be a bit confusing since
strerror takes a positive error code but PTR_ERR returns a negative
number, so we have to do strerror(-PTR_ERR(errp)). Some places got
this wrong already, so introduce a strerrorp function which directly
takes an error pointer.

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

A lot of files rely on include/driver.h including include/of.h (and
this including include/errno.h. include the files explicitly so we can
eventually get rid of including of.h from driver.h

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

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

This phy is found on i.MX6 and i.MX23/28. Currently tested only on i.MX6.
For now we take the easy way out. The phy is enabled upon registration.
More elaborated handling can be added later.

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