mnxti reads return incorrect value when CLIC_ID_WIDTH = 1

Created by: silabs-mateilga

Component:RTL

Reads of csr mnxti, that should return the value of csr mtvt + XLEN/8 * clic_id, does not return correct value when the id width is 1. Debugging with @silabs-oysteink indicates that this applies for all widths < 4.

Reproduce by formally proving ...core_i.clic_assert_i.gen_clic_assertions.a_mnxti_case_1_irq_req_unchanged with branch: https://github.com/silabs-mateilga/core-v-verif/tree/clic_assert_mtvt_fields on the cv32e40s core