sf: probe: Add support for SST_WP

Most of the SST flashes needs to write up using SST_WP, AAI
Word Program, so added a flag param on spi_flash_params table.

SST flashes, which supports SST_WP need to use a WP write
sst_write_wp instead of common flash write.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>

include/spi_flash.h

@@ -17,6 +17,13 @@
 #include <linux/types.h>
 #include <linux/compiler.h>
 
+/* SST specific macros */
+#ifdef CONFIG_SPI_FLASH_SST
+# define SST_WP			0x01	/* Supports AAI word program */
+# define CMD_SST_BP			0x02    /* Byte Program */
+# define CMD_SST_AAI_WP		0xAD	/* Auto Address Incr Word Program */
+#endif
+
 struct spi_flash {
 	struct spi_slave *spi;