msm: mdss: use the correct variable for continuous splash status

The DSI driver checks if continuous splash screen is enabled
via mdss_panel_get_boot_cfg API to MDP driver. In the current code,
we use the wrong variable to check continuous splash screen status.
This might cause display crash during boot up when continuous splash
screen is disabled. Fix this issue by using the correct variable
to check the status.

Change-Id: Iaa752a5c764dbd3ca94a5e14514f9174dad21695
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>