mailbox: pcc: Move bulk of PCCT parsing into pcc_mbox_probe

mainline inclusion
from mainline-v5.16-rc1
commit ce028702
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6Z91B
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.3-rc2&id=ce028702ddbc69743d958f9e20ad0306e4a428fe



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Move the PCCT subspace parsing and allocation into pcc_mbox_probe so
that we can get rid of global PCC channel and mailbox controller data.
It also helps to make use of devm_* APIs for all the allocations.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>