Allow users to select Certified Bluetooth 4.1, rather than
the default not-certified Bluetooth 5, through the use of variable
BT_FW_VERSION="4"
md5sums:
nvm_tlv_3.2.bin ==> 9621f50172f2bfb4f65f8e5c6528b614
rampatch_tlv_3.2.tlv ==> 769e1fc9e5a2061bb3aaa1f32dac3804
Signed-off-by: Francisco Gil <francisco.gilmartinez@digi.com>