input: touchscreen: bu21150: fix for recovery mode

When display's continuous splash is on, blank call from recovery
module returns early. But bu21150 touch AFE driver on getting blank
event can go ahead with display enable and reset GPIO toggling which
will result in bad DSI state.

To fix this, display driver exposes an API to return continuous
splash flag. The touch AFE driver does not toggle display enable/reset
GPIO when continuous splash is on.

Change-Id: Iec73f96b61a4f3a86fe7a7ad40fb368c7cd0178f
Signed-off-by: Jing Lin <jinglin@codeaurora.org>