FROMLIST: MIPS: CPC: Map registers using DT in mips_cpc_default_phys_base()

FROMLIST: MIPS: CPC: Map registers using DT in mips_cpc_default_phys_base()

Reading mips_cpc_base value from the DT allows each platform to
define it according to its needs. This is especially convenient
for MIPS_GENERIC kernel where this kind of information should be
determined in runtime.

Use mti,mips-cpc compatible string with just a reg property to
specify the register location for your platform.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@mips.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
(cherry picked from: https://patchwork.linux-mips.org/patch/18513/)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>