board: tqma6: improve config settings for TQMa6x/MBa6x

board: tqma6: improve config settings for TQMa6x/MBa6x

- imply DM_I2C / DM_SPI / DM_MMC / DM_GPIO: boot relevant

- add BUTTON support
- add gpio LED support
- enable CMD_TEMPERATURE to get query temperature in console
- remove Variants that are Kconfig default
- USB ethernet port is not in use by default, remove ethprime

Signed-off-by: Paul Gerber <Paul.Gerber@tq-group.com>
Signed-off-by: Markus Niebel <Markus.Niebel@ew.tq-group.com>
Signed-off-by: Max Merchel <Max.Merchel@ew.tq-group.com>