brd: add missing MODULE_DESCRIPTION() macro

make allmodconfig && make W=1 C=1 reports:
modpost: missing MODULE_DESCRIPTION() in drivers/block/brd.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240602-md-block-brd-v1-1-e71338e131b6@quicinc.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/brd.c

@@ -296,6 +296,7 @@ static int max_part = 1;
 module_param(max_part, int, 0444);
 MODULE_PARM_DESC(max_part, "Num Minors to reserve between devices");
 
+MODULE_DESCRIPTION("Ram backed block device driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
 MODULE_ALIAS("rd");