drm/i915/gvt: Fix static checker warning on intel_gvt_i2c_handle_aux_ch_write()

Static checker gave warning on:

drivers/gpu/drm/i915/gvt/edid.c:506 intel_gvt_i2c_handle_aux_ch_write()
warn: odd binop '0x0 & 0xff'

We try to return ACK for I2C reply which is defined with 0. Remove
bit shift which caused misleading bit op.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>