drivers: display: ssd1306: determin sh1106 by dts compatibility

Determine sh1106 from the `compatibility` value instead of
the SSD1306_CONTROLLER_TYPE setting.

Change the settings in `boards/shields/ssd1306/sh1106_128x64.overlay`
to follow this change.
Remove the SSD1306_CONTROLLER_TYPE from its Kconfig.defconfig,
and set the `compatibility` to `sinowealth,sh1106`.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>