iwlwifi: acpi: move function to get mcc into acpi code

The iwl_get_bios_mcc() function was in the iwl-nvm-parse.c file, but
it has nothing to do with the NVM.  Move it to fw/acpi.c and rename it
to iwl_acpi_get_mcc().

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>