sf: Add an empty entry to the parameter list

The list is supposed to be terminated with a NULL name, but is not. If a
board probes a chip which does not appear in the table, U-Boot will crash
(at least on sandbox).
Signed-off-by: NSimon Glass <sjg@chromium.org>

drivers/mtd/spi/sf_params.c

@@ -116,6 +116,7 @@ const struct spi_flash_params spi_flash_params_table[] = {
 	{"W25Q64DW",	   0xef6017, 0x0,	64 * 1024,   128, RD_FULL,	    WR_QPP | SECT_4K},
 	{"W25Q128FW",	   0xef6018, 0x0,	64 * 1024,   256, RD_FULL,	    WR_QPP | SECT_4K},
 #endif
+	{},	/* Empty entry to terminate the list */
 	/*
 	 * Note:
 	 * Below paired flash devices has similar spi_flash params.