sh: push-switch: Add missing MODULE_DESCRIPTION() macro

Fixes the following warning when building allmodconfig with W=1 C=1:

WARNING: modpost: missing MODULE_DESCRIPTION() in arch/sh/drivers/push-switch.o

Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20240702-md-sh-arch-sh-drivers-v1-1-2c5d439a5479@quicinc.com


Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>