msm: mdss: fb: fix panel reconfiguration check for format change

Previously output_format is not updated. Update
the new output_format in panel_info.

Change-Id: I8ee76a9fabb5d2a9aa93d5c14deeeef9b26ba78b
Signed-off-by: Venkata Prahlad Valluru <vvalluru@codeaurora.org>