* Derive default interrupt from configured instead of default pin
Derive DEFAULT_RFM69_IRQ_NUM from MY_RFM69_IRQ_PIN instead of
DEFAULT_RFM69_IRQ_PIN so that _NUM does not have to be defined
if _PIN is redefined
* Change default IRQ pin for RFM69/95 on ESP8266 to GPIO5=D1
The originally defined pin GPIO2 prevent ESP8266 from booting,
since it has to be pulled high for booting and DIO0 from the
RFM69 is defaul low.
For this reason, it is improbably that anyone is using the default
and would be affected by this change.
tekka
kvoit