mtd: spi-nor: hisi-sfc: Demote non-conformant kernel-doc

mtd: spi-nor: hisi-sfc: Demote non-conformant kernel-doc

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

 drivers/mtd/spi-nor/controllers/hisi-sfc.c:328: warning: Function parameter or member 'np' not described in 'hisi_spi_nor_register'
 drivers/mtd/spi-nor/controllers/hisi-sfc.c:328: warning: Function parameter or member 'host' not described in 'hisi_spi_nor_register'

Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20201109182206.3037326-8-lee.jones@linaro.org