hw/arm/mps2-tz: Assert if more than one RAM is attached to an MPC

hw/arm/mps2-tz: Assert if more than one RAM is attached to an MPC

Each board in mps2-tz.c specifies a RAMInfo[] array providing
information about each RAM in the board.  The .mpc field of the
RAMInfo struct specifies which MPC, if any, the RAM is attached to.
We already assert if the array doesn't have any entry for an MPC, but
we don't diagnose the error of using the same MPC number twice (which
is quite easy to do by accident if copy-and-pasting structure
entries).

Enhance find_raminfo_for_mpc() so that it detects multiple entries
for the MPC as well as missing entries.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210409150527.15053-3-peter.maydell@linaro.org