RTC_CNTL_COCPU_SHUT_RESET_EN register was being reset during ULP RISC-V
initialization which does not let the ULP RISC-V coprocessor to reset
after it goes to halt. For proper operation of the coprocessor, it must
be reset after each cycle and hence this commit keeps
RTC_CNTL_COCPU_SHUT_RESET_EN set.
This commit refactors the ulp component.
Files are now divided based on type of ulp, viz., fsm or risc-v.
Files common to both are maintained in the ulp_common folder.
This commit also adds menuconfig options for ULP within the ulp
component instead of presenting target specific configuations for ulp.
