linux-firmware: offer two versions of firmware for CYW4339

linux-firmware: offer two versions of firmware for CYW4339

According to commit 6f6c2fb321, AP6335 module used in PICO-PI-IMX7D works
only with firmware from `linux-firmware`. However, firmware from
`cypress-firmware` suite is directly from the chip company (Infineon) and
is actually newer.

Instead of dropping the firmware from Infineon, create a package named
`brcmfmac-firmware-4339-sdio`, and keep the Infineon version of
`cypress-firmware-4339-sdio` around.

This gives us devs the option to choose. Also, it means that

 - packages `brcmfmac-firmware-*` uniformly come from `linux-firmware`
 - packages `cypress-firmware-*` uniformly come from `cypress-firmware`

so hopefully brings more clarity.

Tested-by: Lech Perczak <lech.perczak@gmail.com>
Signed-off-by: Kuan-Yi Li <kyli@abysm.org>