mfd: tc3589x: Reform device tree probing

This changes the following mechanisms in the TC3589x device tree
probing path:

- Use the .of_match_table in struct device_driver to match the
  device in the device tree.
- Add matches for the proper compatible strings "toshiba,..."
  and all sub-variants, just as is done for the .id matches.
- Move over all the allocation of platform data etc to the
  tc3589x_of_probe() function and follow the pattern of passing
  a platform data pointer back, or an error pointer on error,
  as found in the STMPE driver.
- Match the new (proper) compatible strings for the GPIO and
  keypad MFD cells.
- Use of_device_is_compatible() rather than just !strcmp()
  to discover which cells to instantiate.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>