ath79: cleanup DTS for ALLNET ALL-WAP02860AC

ath79: cleanup DTS for ALLNET ALL-WAP02860AC

use qca955x_senao_loader.dtsi
because it is the same hardware / partitioning
and some cleanup

Effects:

nodes to match similar boards
 - keys
 - eth0
 - pcie0

bumps SPI frequency to 40 MHz

removes &pll node:
the property is defined in qca955x.dtsi

removes qca,no-eeprom:
has no effect with mtd-cal-data property
(also spelling)

Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Michael Pratt <mcpratt@pm.me>
(cherry picked from commit e800da9d5c87d276806284cf2183994ea7fe083e)