spi: flash: provide the proper length of the buffer in flash_write()

source/drivers/spi_flash.c

@@ -126,15 +126,14 @@ static size_t spi_flash_write(struct flash_dev *dev, uint32_t addr,
 	spi_flash_write_enable(dev);
 
 	while (len) {
-		spi_flash_wait(dev);
-
 		cmd[0] = SPI_FLASH_PAGE_PROGRAM;
 		spi_flash_addr(cmd, addr);
 
 		nbytes = min(len, 32);
 
 		memmove(cmd + 4, data, nbytes);
-		spi_tx_rx(spi_dev, NULL, 0, cmd, sizeof cmd);
+		spi_tx_rx(spi_dev, NULL, 0, cmd, 4 + nbytes);
+		spi_flash_wait(dev);
 
 		addr += nbytes;
 		data += nbytes;
@@ -142,7 +141,6 @@ static size_t spi_flash_write(struct flash_dev *dev, uint32_t addr,
 		ret += nbytes;
 	}
 
-	spi_flash_wait(dev);
 	spi_flash_write_disable(dev);
 
 	return ret;