leds: pca955x: Add an IBM software implementation of the PCA9552 chip

IBM created an implementation of the PCA9552 on a PIC16F
microcontroller. The I2C device addresses are different from the
hardware PCA9552, so add a new compatible string and associated
platform data to be able to probe this device.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>