MIPS: CM: make use of mips_cm_{lock,unlock}_other

MIPS: CM: make use of mips_cm_{lock,unlock}_other

Document that CPC core-other accesses must take place within the bounds
of the CM lock, and begin using the CM lock functions where we access
the GCRs of other cores. This is required because with CM3 the CPC began
using GCR_CL_OTHER instead of CPC_CL_OTHER.

Signed-off-by: Paul Burton <[email protected]>
Cc: [email protected]
Cc: Rusty Russell <[email protected]>
Cc: Andrew Bresticker <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: [email protected]
Cc: Niklas Cassel <[email protected]>
Cc: Ezequiel Garcia <[email protected]>
Cc: Markos Chandras <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/11208/
Signed-off-by: Ralf Baechle <[email protected]>