Staging: sm750fb: Rename displayControlAdjust_SM750E

Staging: sm750fb: Rename displayControlAdjust_SM750E

Rename function displayControlAdjust_SM750E to
display_control_adjust_SM750E. This follows snakecase naming convention
and ensures a consistent naming style throughout the file. Issue found by
checkpatch.

Mutes the following error:
CHECK:Avoid CamelCase: <displayControlAdjust_SM750E>

Signed-off-by: Dorcas AnonoLitunya <anonolitunya@gmail.com>
Link: https://lore.kernel.org/r/20231016201434.7880-2-anonolitunya@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>