greybus: add missing MODULE_DESCRIPTION() macros

make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/greybus/greybus.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/greybus/gb-es2.o

Add all missing invocations of the MODULE_DESCRIPTION() macro.
Acked-by: Alex Elder <elder@kernel.org>
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240626-md-drivers-greybus-v2-1-d520ffb9a489@quicinc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/greybus/core.c

@@ -375,5 +375,6 @@ static void __exit gb_exit(void)
 	tracepoint_synchronize_unregister();
 }
 module_exit(gb_exit);
+MODULE_DESCRIPTION("Greybus core driver");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");

drivers/greybus/es2.c

@@ -1456,5 +1456,6 @@ static struct usb_driver es2_ap_driver = {
 
 module_usb_driver(es2_ap_driver);
 
+MODULE_DESCRIPTION("Greybus AP USB driver for ES2 controller chips");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");