CORE_V_MCU high level design specs

Created by: cst-rameez

Adding high level design specs for the IPs which have insufficient information in core_v_mcu user manual https://docs.openhwgroup.org/projects/core-v-mcu/

Following are CORE-V-MCU IP blocks whose documents are updated: APB Advanced Timer APB SoC Controller APB PLL Interface APB_GPIO APB Timer ABP I2C Slave APB Event Control UDMA CAMERA Interface UDMA SD Card Interface