i2c: i2c-qcom-geni: Enable shared flag in GSI mode only

The shared flag should only be enabled in GSI mode only to
handle multi-EE GSI usecase.

Change-Id: I4f1c4d82c6da488fefab619f3fad03046f68ba0b
Signed-off-by: Vipin Deep Kaur <vkaur@codeaurora.org>