platform: generic: allwinner: fix OF process for T-HEAD c9xx pmu

T-HEAD c9xx pmu needs to clear OV bits of MCOUNTEROF in any condition
to avoid unnecessary OF interrupts.

In addition, the S-mode SCOUNTEROF only have OF bit set when the related
bits of MCOUNTERWEN is set, so also configure MCOUNTERWEN to allow kernel
to access valid SCOUNTEROF.

Signed-off-by: Haijiao Liu <haijiao.liu@sophgo.com>
Co-authored-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Samuel Holland <samuel@sholland.org>