staging: pi433: fix CamelCase for newValue

Local variable storing the new value for bandwidth register
so replace with bandwidth.

Fixes checkpatch warnings:

  CHECK: Avoid CamelCase: <newValue>

Signed-off-by: Valentin Vidic <Valentin.Vidic@CARNet.hr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>