firmware: FIRMWARE_NAME_MAX removal

As we're allocating the firmware name dynamically, we no longer need this
definition.
This patch must be applied only after the 5 previous patches from this pacth
set have been applied.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>