This adds version 1.5 of the firmware for i2400m based devices (Intel
Wireless WiMAX Connection 5x50) and adds support for the 6x50
series.

The 1.3 version is purged as it is was never supported by a released kernel.
Signed-off-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>