Recently driver has implemented a new doorbell mechanism via bsg.  The new
doorbell tells driver the exact buffer size application has where driver
can fill it up with events. The old doorbell guestimated application buffer
size is 256.

Remove duplicate functionality, the application has moved on to the new
doorbell interface.

Link: https://lore.kernel.org/r/20220607044627.19563-9-njavali@marvell.comSigned-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>