Some ChromeOS EC devices (such as the Framework Laptop) only map I/O
ports 0x800-0x807. Making the larger reservation required by the non-MEC
LPC (the 0xFF ports for the memory map, and the 0xFF ports for the
parameter region) is non-viable on these devices.

Since we probe the MEC EC first, we can get away with a smaller
reservation that covers the MEC EC ports. If we fall back to classic
LPC, we can grow the reservation to cover the memory map and the
parameter region.

cros_ec_lpc_probe also interacted with I/O ports 0x800-0x807 without a
reservation. Restructuring the code to request the MEC LPC region first
obviates the need to do so.
Signed-off-by: Dustin L. Howett <dustin@howett.net>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220217165930.15081-3-dustin@howett.net