platform/x86: mlx-platform: Allow mlxreg-io driver activation for more systems

Allow mlxreg-io platform driver activation for more system types, in
particular for MSN21xx, MSN201x types, which have reset causes bits
slightly different from the default configuration.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>