mtd: rawnand: gpmi: remove redundant variable payload_virt

Variable payload_virt is being assigned but is never used hence it is
redundant and can be removed.

Cleans up clang warning:
warning: variable 'payload_virt' set but not used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c

@@ -957,7 +957,6 @@ static int gpmi_ecc_read_page_data(struct nand_chip *chip,
 	struct gpmi_nand_data *this = nand_get_controller_data(chip);
 	struct bch_geometry *nfc_geo = &this->bch_geometry;
 	struct mtd_info *mtd = nand_to_mtd(chip);
-	void          *payload_virt;
 	dma_addr_t    payload_phys;
 	unsigned int  i;
 	unsigned char *status;
@@ -967,7 +966,6 @@ static int gpmi_ecc_read_page_data(struct nand_chip *chip,
 
 	dev_dbg(this->dev, "page number is : %d\n", page);
 
-	payload_virt = this->payload_virt;
 	payload_phys = this->payload_phys;
 
 	if (virt_addr_valid(buf)) {
@@ -976,7 +974,6 @@ static int gpmi_ecc_read_page_data(struct nand_chip *chip,
 		dest_phys = dma_map_single(this->dev, buf, nfc_geo->payload_size,
 					   DMA_FROM_DEVICE);
 		if (!dma_mapping_error(this->dev, dest_phys)) {
-			payload_virt = buf;
 			payload_phys = dest_phys;
 			direct = true;
 		}