forked from Mirrors/opensbi

Currently, csr_read/write_num functions are used to read/write PMP related CSRs where CSR value is decided at runtime. Expand this function to include PMU related CSRs as well. Reviewed-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Xiang W <wxjstz@126.com> Signed-off-by: Atish Patra <atish.patra@wdc.com>