iwlwifi: 8000: fix MODULE_FIRMWARE input

The firwmare name for 8000 is iwlwifi-8000C. The C is
appended based on a value read from a register. This
allows to load different firwmare versions based on
the hardware step during development. Now that the
hardware development is completed, we can hard code
the 'C' and along the way, fix the input to
MODULE_FIRMWARE.

This fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=116041



Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>