Convert to static inline functions and use lower case letters for function
names. Also, include mach/debug_ll.h when an architecture provides support
for debug_ll, not only when it's actually enabled. This allows architecures
to put some UART initialization code into mach/debug_ll.h which is compiled
out when debug_ll is disabled.

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

To make early debugging on i.MX a bit simpler. This uses a similar
magic than the kernel does.

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

This adds lowlevel debug functions for i.MX. As we have a great variety
of different UARTs on i.MX currently no Kconfig support for chosing the
correct one is added. Instead we expect the user to add the correct
define and issue a compiler warning if he hasn't.

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