M451 series can classify by M45xD/M45xC and M45xG/M45xE. To support this
classification:
1. Create TARGET_M45xD_M45xC and TARGET_M45xG_M45xE targets.
2. Mark NUMAKER_PFM_M453 belongs to TARGET_M45xG_M45xE by 'extra_labels_add'
in targets.json.
3. Fix pin name table according to the classification.
4. Fix pinmap table according to the classification.
1. Modify PinMode enum to fully support GPIO I/O modes.
2. Translate input pull mode/direction to I/O mode, where H/W doesn't support
separate configuration for input pull mode/direction.
3. Allow for configuring I/O mode in addition to input pull mode.
Chun-Chieh Li