misc: Fix db_offset calculation

misc: Fix db_offset calculation

db_offset used to be calculated through pointer arithmetic. Pointer
arithmetic increments the address by the size of the data type the
pointer is pointing at. In the previous db_offset calculation, that
was a uint32_t, which means the input was multiplied by 4, which is
sizeof(uint32_t)

This patch multiplies the input value by sizeof(uint32_t) before
assigning it to db_offset.

Change-Id: I9042560303ae6b8b1054b98e9a16a9da27843bb2
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/32678
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Alexandru Duțu <alexandru.dutu@amd.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>