[MIPS] Add missing ifdef arch/mips/pmc-sierra/yosemite/setup.c

early_serial_setup is only defined when CONFIG_SERIAL_8250 is set.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
1 file changed