The CONFIG_BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP option is enabled
by default for the following examples:
- system/deep_sleep,
- system/ulp,
- system/ulp_adc.
To increase the chances that the examples work out of the box, this
change is raising the default deep sleep wakeup delay to 1ms.
If GPIO15 is low at startup, ROM code takes less time to execute
(because no logging is performed), so more time may be needed to allow
flash chip to become ready.