Provide a helper to detect the enabled UART device during runtime. This
lower the integration effort and make it more straight forward for
'simple' use-cases with a single UART enabled. If multiple UARTs are
enabled the first enabled is returned.
The auto-detection is enabled by setting IMX_BOOT_UART_BASE=0 to keep
the backward compatibility. For more advanced use-cases (multiple UARTs
are enabled) the user still has to provide the correct base address.
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Change-Id: I300a167e1a10f9aa991c8d1c3efe2c6b23f56c47
df730d94cb