msm: camera: isp: Reset offline context flag

This change resets the offline context flag,
otherwise the packet may be applied to HW immediately
if this context is offline context last time.

CRs-Fixed: 2696977
Change-Id: I2fc836f7ba2889ec62273c3b12cc4050736f587b
Signed-off-by: zhuo <zhuo@codeaurora.org>