bus: mhi: host: Use mhi_soc_reset() API in place of register write

Currently, a direct register write is used when ramdump collection
in panic path occurs. Replace that with new mhi_soc_reset() API
such that a controller defined reset() function is exercised if
one is present and the regular SOC reset is done if it is not.

Signed-off-by: Qiang Yu <quic_qianyu@quicinc.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>