MIPS: Fix early CM probing

MIPS: Fix early CM probing

Commit c014d164f21d ("MIPS: Add platform callback before initializing
the L2 cache") added a platform_early_l2_init function in order to allow
platforms to probe for the CM before L2 initialisation is performed, so
that CM GCRs are available to mips_sc_probe.

That commit actually fails to do anything useful, since it checks
mips_cm_revision to determine whether it should call mips_cm_probe but
the result of mips_cm_revision will always be 0 until mips_cm_probe has
been called. Thus the "early" mips_cm_probe call never occurs.

Fix this & drop the useless weak platform_early_l2_init function by
simply calling mips_cm_probe from setup_arch. For platforms that don't
select CONFIG_MIPS_CM this will be a no-op, and for those that do it
removes the requirement for them to call mips_cm_probe manually
(although doing so isn't harmful for now).

Signed-off-by: Paul Burton <[email protected]>
Reviewed-by: Alexander Sverdlin <[email protected]>
Cc: Andrzej Hajda <[email protected]>
Cc: Aaro Koskinen <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Peter Hurley <[email protected]>
Cc: Leonid Yegoshin <[email protected]>
Cc: Jaedon Shin <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Jonas Gorski <[email protected]>
Cc: Markos Chandras <[email protected]>
Cc: [email protected]
Cc: [email protected]
Patchwork: https://patchwork.linux-mips.org/patch/12475/
Signed-off-by: Ralf Baechle <[email protected]>