mfd: smsc-ece1099: Remove driver

This MFD driver has no user. The keypad driver of this device never made
it into the kernel. Therefore, this driver is useless. Remove it.

Signed-off-by: Michael Walle <michael@walle.cc>
Cc: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/driver-api/index.rst

@@ -98,7 +98,6 @@ available subsections can be seen below.
    rfkill
    serial/index
    sm501
-   smsc_ece1099
    switchtec
    sync_file
    vfio-mediated-device

Documentation/driver-api/smsc_ece1099.rst

@@ -1,60 +0,0 @@
-=================================================
-Msc Keyboard Scan Expansion/GPIO Expansion device
-=================================================
-
-What is smsc-ece1099?
-----------------------
-
-The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
-or GPIO Expansion device. The device supports a keyboard
-scan matrix of 23x8. The device is connected to a Master
-via the SMSC BC-Link interface or via the SMBus.
-Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
-are multiplexed with GPIOs.
-
-Interrupt generation
---------------------
-
-Interrupts can be generated by an edge detection on a GPIO
-pin or an edge detection on one of the bus interface pins.
-Interrupts can also be detected on the keyboard scan interface.
-The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
-any bit in one of the Interrupt Status registers is 1 and
-the corresponding Interrupt Mask bit is also 1.
-
-In order for software to determine which device is the source
-of an interrupt, it should first read the Group Interrupt Status Register
-to determine which Status register group is a source for the interrupt.
-Software should read both the Status register and the associated Mask register,
-then AND the two values together. Bits that are 1 in the result of the AND
-are active interrupts. Software clears an interrupt by writing a 1 to the
-corresponding bit in the Status register.
-
-Communication Protocol
-----------------------
-
-- SMbus slave Interface
-	The host processor communicates with the ECE1099 device
-	through a series of read/write registers via the SMBus
-	interface. SMBus is a serial communication protocol between
-	a computer host and its peripheral devices. The SMBus data
-	rate is 10KHz minimum to 400 KHz maximum
-
-- Slave Bus Interface
-	The ECE1099 device SMBus implementation is a subset of the
-	SMBus interface to the host. The device is a slave-only SMBus device.
-	The implementation in the device is a subset of SMBus since it
-	only supports four protocols.
-
-	The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
-	only valid SMBus protocols for the device.
-
-- BC-LinkTM Interface
-	The BC-Link is a proprietary bus that allows communication
-	between a Master device and a Companion device. The Master
-	device uses this serial bus to read and write registers
-	located on the Companion device. The bus comprises three signals,
-	BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
-	clock, BC_CLK, and the Companion device is the source for an
-	independent asynchronous interrupt signal, BC_INT#. The ECE1099
-	supports BC-Link speeds up to 24MHz.