msm: camera: isp: Remove update of framedrop and IRQ subsampling

Framedrop update and IRQ subsampling update is moved to HFR blob
update from buffer config. So remove it from update_buf()to avoid
incorrect updates.

Change-Id: I85e2dddf1ee6141dbd44a0671d5281562ca8c4d5
Signed-off-by: Harsh Shah <harshs@codeaurora.org>