Fixes the following W=1 kernel build warning(s):

 drivers/mtd/nand/onenand/onenand_bbt.c:33: warning: Function parameter or member 'buf' not described in 'check_short_pattern'
 drivers/mtd/nand/onenand/onenand_bbt.c:33: warning: Function parameter or member 'len' not described in 'check_short_pattern'
 drivers/mtd/nand/onenand/onenand_bbt.c:33: warning: Function parameter or member 'paglen' not described in 'check_short_pattern'
 drivers/mtd/nand/onenand/onenand_bbt.c:33: warning: Function parameter or member 'td' not described in 'check_short_pattern'
 drivers/mtd/nand/onenand/onenand_bbt.c:57: warning: Function parameter or member 'mtd' not described in 'create_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:57: warning: Function parameter or member 'buf' not described in 'create_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:57: warning: Function parameter or member 'bd' not described in 'create_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:57: warning: Function parameter or member 'chip' not described in 'create_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:132: warning: Function parameter or member 'mtd' not described in 'onenand_memory_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:132: warning: Function parameter or member 'bd' not described in 'onenand_memory_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:145: warning: Function parameter or member 'mtd' not described in 'onenand_isbad_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:145: warning: Function parameter or member 'offs' not described in 'onenand_isbad_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:145: warning: Function parameter or member 'allowbbt' not described in 'onenand_isbad_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:182: warning: Function parameter or member 'mtd' not described in 'onenand_scan_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:182: warning: Function parameter or member 'bd' not described in 'onenand_scan_bbt'
 drivers/mtd/nand/onenand/onenand_bbt.c:230: warning: Function parameter or member 'mtd' not described in 'onenand_default_bbt'

Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-7-lee.jones@linaro.org