ARM: OMAP: hwmod: Use sysc_fields->srst_shift and get rid of hardcoded SYSC_TYPE2_SOFTRESET_MASK
This is useful when we have broken type2 compliant IPs' where
the softreset shift is not the same as SYSC_TYPE2_SOFTRESET_SHIFT
and hence is overridden using sysc_fields->srst_shift.
We have at least one such instance now with onchip keypad on OMAP5
which has a different softreset shift as compared to other type2
IPs'.