soc: wcd-spi-ac: add wcd spi access control driver

Add driver to perform WCD SPI bus arbitration between two
masters. The two masters could reside on two different
processors and QMI is used to arbitrate the bus access.
This driver also exposes character driver interface to
userspace to indicate use case start/stop, etc.

Change-Id: I4f6fe6bb0bca524f10a34cf89149c6b2055b00e1
Signed-off-by: Bhalchandra Gajare <gajare@codeaurora.org>