MSoM: fixes power leakage when devices are in STOP/ULP mode

[XuGuohui]

Problem

MSoMs will leak current on PB12 (QSPI_IO3) and SWD_DATA when the device is in STOP/ULP mode.

Solution

1. There is no external pull-up resistor on PB12. Configuring PB12 as pull-up before sleep and restore it to no-pull after waking up can reduce ~1mA.
2. There is an external pull-up resistor on SWD_DATA. Configures SWD_DATA to pull-up before entering sleep mode can save us ~100uA.

Steps to Test

Flash the following user app to estimate the STOP mode power consumption.

Example App

#include "Particle.h"

SYSTEM_MODE(SEMI_AUTOMATIC);

Serial1LogHandler logHandler(115200, LOG_LEVEL_ALL);

void setup() {
    delay(5s);
    System.sleep(SystemSleepConfiguration().mode(SystemSleepMode::STOP).gpio(D0, FALLING));
}

void loop() {

}

References

N/A

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Completeness

• User is totes amazing for contributing!
• Contributor has signed CLA (Info here)
• Problem and Solution clearly stated
• Run unit/integration/application tests on device
• Added documentation
• Added to CHANGELOG.md after merging (add links to docs and issues)