SPI: Add support for TSC2301 protocol driver

This adds a driver for TSC2301 including support for audio, keypad and
touchscreen. Patch is originally developed for Nokia N800 by Imre Deak,
Jarkko Nikula, Jarkko Oikarinen and Juha Yrjola.

Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>

diff --cc drivers/spi/Kconfig
Simple merge

diff --cc drivers/spi/Makefile
Simple merge

diff --cc drivers/spi/tsc2301-core.c
Simple merge

diff --cc drivers/spi/tsc2301-mixer.c
Simple merge

diff --cc include/linux/spi/tsc2301.h
Simple merge