ASoC: wcd: correct data type in interrupt handler

The interrupt handler uses one byte to read the
interrupt status register. This is fine with 32-bit
architecture, but with 64 bit, this results in reading
the latched status interrupt register for analog part
incorrectly and thus the interrupt handler is not
dispatched.

CRs-Fixed: 717831
Change-Id: Ifd9d9bdc3ea2d393f44911d4588ef2f483c8a028
Signed-off-by: Simmi Pateriya <simmip@codeaurora.org>