i2c/chips: Remove deprecated pca9539 driver

The pca9539 driver in drivers/i2c/chips which just exports its registers to
sysfs is superseded by drivers/gpio/pca953x.c which properly uses the gpiolib.
As this driver has been deprecated for more than a year, finally remove it.

Signed-off-by: Wolfram Sang <[email protected]>
Acked-by: Ben Gardner <[email protected]>
Signed-off-by: Jean Delvare <[email protected]>

Documentation/i2c/chips/pca9539

@@ -1,58 +0,0 @@
-Kernel driver pca9539
-=====================
-
-NOTE: this driver is deprecated and will be dropped soon, use
-drivers/gpio/pca9539.c instead.
-
-Supported chips:
-  * Philips PCA9539
-    Prefix: 'pca9539'
-    Addresses scanned: none
-    Datasheet:
-        http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf
-
-Author: Ben Gardner <[email protected]>
-
-
-Description
------------
-
-The Philips PCA9539 is a 16 bit low power I/O device.
-All 16 lines can be individually configured as an input or output.
-The input sense can also be inverted.
-The 16 lines are split between two bytes.
-
-
-Detection
----------
-
-The PCA9539 is difficult to detect and not commonly found in PC machines,
-so you have to pass the I2C bus and address of the installed PCA9539
-devices explicitly to the driver at load time via the force=... parameter.
-
-
-Sysfs entries
--------------
-
-Each is a byte that maps to the 8 I/O bits.
-A '0' suffix is for bits 0-7, while '1' is for bits 8-15.
-
-input[01]     - read the current value
-output[01]    - sets the output value
-direction[01] - direction of each bit: 1=input, 0=output
-invert[01]    - toggle the input bit sense
-
-input reads the actual state of the line and is always available.
-The direction defaults to input for all channels.
-
-
-General Remarks
----------------
-
-Note that each output, direction, and invert entry controls 8 lines.
-You should use the read, modify, write sequence.
-For example. to set output bit 0 of 1.
-  val=$(cat output0)
-  val=$(( $val | 1 ))
-  echo $val > output0
-