platform: msm: qcom-geni-se: Modify GSI switch sequence

Modify the function call that switches to GSI DMA mode to keep the error
and GP (general purpose) IRQ bits enabled but only disables the datapath
related IRQ bits.

Change-Id: Ib88e11f0eeabcb62dbd88f37a5d468a36930b1a4
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>