video: ssd1307fb: Add support for SSD1306 OLED controller

The Solomon SSD1306 OLED controller is very similar to the SSD1307,
except for the fact that the power is given through an external PWM for
the 1307, and while the 1306 can generate its own power without any PWM.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/video/ssd1307fb.txt

 * Solomon SSD1307 Framebuffer Driver
 
 Required properties:
-  - compatible: Should be "solomon,ssd1307fb-<bus>". The only supported bus for
-    now is i2c.
+  - compatible: Should be "solomon,<chip>fb-<bus>". The only supported bus for
+    now is i2c, and the supported chips are ssd1306 and ssd1307.
   - reg: Should contain address of the controller on the I2C bus. Most likely
          0x3c or 0x3d
   - pwm: Should contain the pwm to use according to the OF device tree PWM
-         specification [0]
+         specification [0]. Only required for the ssd1307.
   - reset-gpios: Should contain the GPIO used to reset the OLED display
+  - solomon,height: Height in pixel of the screen driven by the controller
+  - solomon,width: Width in pixel of the screen driven by the controller
+  - solomon,page-offset: Offset of pages (band of 8 pixels) that the screen is
+    mapped to.
 
 Optional properties:
   - reset-active-low: Is the reset gpio is active on physical low?