fastmodel: improve debug message for resource not found

The conversion logic between gem5 register id and iris resouce id is
duplicated in read and write function. Some of them also doesn't handle
the invalid id correctly. This change wraps the logic, fixes them, and
improves the debug messages by printing the register names.

Change-Id: I093d05f5f06d804d5f01988c2a7ffa60244c5516
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64651
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabeblack@google.com>
2 files changed