* Hold GC1109 PA_POWER and PA_EN during deep sleep for LNA RX wake
Use rtc_gpio_hold_en to latch PA_POWER (LDO) and PA_EN (CSD) HIGH
during deep sleep so the GC1109 LNA remains powered for wake-on-packet
RX. Previously these pins used weak pull-ups which could lose state.
On deep sleep wake, skip these pins in the blanket RTC hold release and
instead release them in SX126xInterface::init() after GPIO registers are
set HIGH first, avoiding a power glitch on the GC1109.
Trade-off: ~6.5mA additional deep sleep current for significantly
improved wake-on-packet RX sensitivity (~17dB).
Reference: https://github.com/meshcore-dev/MeshCore/pull/1600
* Add LDO startup delay before GC1109 chip enable
TLV75733P LDO has ~550us startup time (datasheet tSTR). On cold boot,
wait 1ms for VBAT to stabilise before driving CSD/CPS, per GC1109
power-on sequence requirement. On deep sleep wake the LDO is held on
via RTC latch so no delay is needed.
The previous PSK check was broken from its introduction in #4643 —
memcmp was used in boolean context without comparing to 0, inverting
the condition. Since no one noticed for over a year, the PSK-based
filtering provided no practical value. Simplifying to always respect
the sender's preference is both more correct and easier to reason about.
Wessel