qup_i2c: Initial implementation of I2C mini-core driver for QUP

QUP (Qualcomm Universal Peripheral engine) hardware provides FIFO
based data path to mini cores like I2C. i2c-qup driver communicates
with the QUP and its FIFOs.
Advantages of this driver include 1-interrupt per FIFO/BLOCK number
of byte unlike 1-interrupt-per-byte of i2c-msm.
Since the QUP hardware communicates with I2C mini core, and this
driver communicates with QUP hardware, driver communicating with
I2C hardware directly (like i2c-msm) can't be used to communicate
with QUP. QUP has FIFO mode and BLOCK mode. FIFO mode can be used
if the data transfer size is less than FIFO size. BLOCK mode should
be used for transfers greater than FIFO size.
FIFO mode is supported in this initial implementation.

Signed-off-by: Sagar Dharia <sdharia@quicinc.com>