i2c: designware: Introduce semaphore reservation timer to AMDPSP driver

In order to optimize performance, limit amount of back and forth
transactions between x86 and PSP. This is done by introduction of
semaphore reservation period - that is window in which x86 isn't
releasing the bus immediately after each I2C transaction.

In order to protect PSP from being starved while waiting for
arbitration, after a programmed time bus is automatically released by a
deferred function.

Signed-off-by: Jan Dabros <jsd@semihalf.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
[wsa: removed an unneeded empty line]
Signed-off-by: Wolfram Sang <wsa@kernel.org>