T-HEAD c9xx pmu only needs to clear OV bits of MCOUNTEROF when MOIP bit
of MIP is set, so correct the MIP value check to avoid race conditions
during processing interrupt.
In addition, the S-mode scounterof only have OV 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>
270f27b81b