Add Makefile to make yocto install NXP WLAN firmware binaries easily.
Usage:
1. Specify the installation directory:
make install INSTALLDIR=${DEPLOYDIR}
2. Use the default directory wlan_fw:
make install
3. Clean up the installation directory:
make clean / make clean INSTALLDIR=${DEPLOYDIR}
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>