This adds support for early serial debugging via the built in
port on IBM/AMCC PowerPC 44x CPUs. It uses a bolted TLB entry in
address space 1 for the UART's mapping, allowing robust debugging both
before and after the initialization of the MMU.
Signed-off-by: David Gibson <[email protected]>
Signed-off-by: Paul Mackerras <[email protected]>