mtd: m25p80: Use SPI_MEM_OP_NO_DUMMY instead of SPI_MEM_OP_DUMMY(0, x)

SPI_MEM_OP_DUMMY(0, x) means there's 0 dummy bytes to send, which is
similar to SPI_MEM_OP_NO_DUMMY except it's less clear. Use
SPI_MEM_OP_NO_DUMMY instead of SPI_MEM_OP_DUMMY(0, x) in
m25p80_write().
Also stop updating op.dummy.buswidth since this value is only
meaningful if you have dummy bytes.

Reported-by: Cyrille Pitchen <cyrille.pitchen@microchip.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>

drivers/mtd/devices/m25p80.c

@@ -68,7 +68,7 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 	struct spi_mem_op op =
 			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
 				   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
-				   SPI_MEM_OP_DUMMY(0, 1),
+				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
 	size_t remaining = len;
 	int ret;
@@ -76,7 +76,6 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 	/* get transfer protocols. */
 	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
 	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
-	op.dummy.buswidth = op.addr.buswidth;
 	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
 
 	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)