video: st7586s: Fix the st7568s code to handle the new type of display

- use 3 pixels per byte instead of 2

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
arm: pia-am335x-em: Fix exported display buttons and leds

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
video: st7586s: Adjust display contrast

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>
Merge branch 'pia335x-em' into pia335x-dev

* pia335x-em:
  video: st7586s: Adjust display contrast
  arm: pia-am335x-em: Fix exported display buttons and leds
  video: st7586s: Fix the st7568s code to handle the new type of display
arm: pia-am335x: use 256 Byte eeprom as default ID eeprom

- the different piA boards use different ID EEPROMs some with a UUID,
  others without, some 128 Byte others with 256.
  The 256 byte EUI/UUID eeproms (e.g. 24AA02E48T) use the first
  128 bytes as normal EEPROM and the second 128 bytes in a read-only
  configuration.
- To make sure, we have access to all data of the various variants
  switch the default config from 1KBit to 2KBit with read-only second
  half.

Signed-off-by: Björn Krombholz <b.krombholz@pironex.de>