Staging: cxt1e1: Kconfig: SBE_PMCC4_NCOMM can not be compiled as module, adjust help description

The Kconfig description for CONFIG_SBE_PMCC4_NCOMM says:

  If you have purchased this optional support you must say Y or M
  here to allow the driver to operate with the NCOMM product.

This is not correct as it can not be built as module,
this patch updates the description accordingly.

Signed-off-by: Michael Prokop <mika@grml.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>