rtl826x-firmware: ship rtl8261n and rtl8264b in single firmware package

rtl826x-firmware: ship rtl8261n and rtl8264b in single firmware package

The firmware loading does not depend (solely) on the PHY id. The driver
needs to read out the vendor version id of the PHY before it can decide
which firmware file needs to be loaded.

A split in an RTL8261N and an RTL8264B firmware package is therefore
misleading. And it could even be that a product ships an RTL8264B but
switches the revision of the chip in the middle of its product lifetime. In
this case, the first identification based on the chip ID or the actual chip
ID for the OpenWrt porter might fail for another user with a later/earlier
produced device.

Shipping both files in the same package avoids this problem. Only the "low
power" firmware package is slightly misleading because there is only a
RTL8261N firmware binary for low power but no corresponding RTL8264B
version. It will ship simply the non-low power version for RTL8264B.

Suggested-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Link: https://github.com/openwrt/openwrt/pull/23947
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>