realtek: pcs: rtl931x: drop chiptype 1 support

realtek: pcs: rtl931x: drop chiptype 1 support

From the Realtek SDK we know that the chip type tell us whether a chip
is a normal chip or an engineering sample/testchip [1]. Such engineering
samples likely never reach any consumer device, only some initial
development boards. So far we haven't encountered any device with that,
thus the code paths handling this are practically dead and can hardly be
checked of they work properly. To focus on support for the devices we
actually have, drop support for such engineering samples/testchips. This
may be readded later if there's sufficient need for this.

[1] https://github.com/plappermaul/realtek-doc/blob/3261cf2e6150a519a1d50d1afecd7ad98644cdd6/sources/rtk-dms1250/system/drv/swcore/chip_probe.c#L345

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/21858
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>