serial: msm_geni_serial: Disable Flow only for HSUART usecase

This change restricts disabling of Flow control and interrupts
only for HSUART case. Fundamentally Console usecase need not
have flow control need as part of baud rate change. Also do not
touch interrupts for console usecase as it results into imbalance
of the irq.

Change-Id: Ic6964f5b18c8dc4223a2b2a68f16af33359b3e6e
Signed-off-by: Mukesh Kumar Savaliya <msavaliy@codeaurora.org>