dsp56k: add missing MODULE_DESCRIPTION() macro

dsp56k: add missing MODULE_DESCRIPTION() macro

With ARCH=m68k, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/char/dsp56k.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20240617-md-m68k-drivers-char-dsp56k-v1-1-56e435ffa664@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>