HID: add experimental access to PicoLCD device's EEPROM and FLASH

The PicoLCD device has a small amount of EEPROM and also provides access
to its FLASH where firmware and splash image are saved.
In flasher mode FLASH access is the only active feature.

Give read/write access to both via debugfs files.

NOTE: EEPROM and FLASH access should be switched to better suited API,
      until then the will reside in debugfs

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/Kconfig

@@ -281,9 +281,9 @@ config HID_PICOLCD
 	  - Backlight control         (needs CONFIG_BACKLIGHT_CLASS_DEVICE)
 	  - Contrast control          (needs CONFIG_LCD_CLASS_DEVICE)
 	  - General purpose outputs   (needs CONFIG_LEDS_CLASS)
+	  - EEProm / Flash access     (via debugfs)
 	  Features that are not (yet) supported:
 	  - IR
-	  - EEProm / Flash access
 
 config HID_QUANTA
 	tristate "Quanta Optical Touch"