firmware: atm/ueagle-atm: prepare for FIRMWARE_NAME_MAX removal

We're going to remove the FIRMWARE_NAME_MAX definition in order to avoid any
firmware name length restriction.
This patch replaces the shared FIRMWARE_NAME_MAX definition with a ueagle
local one.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Cc: Damien Bergamini <damien.bergamini@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>