mx6q: mx6qsabrelite: Conditionally define macros for environment in serial flash

The default settings store the persistent environment on SD card
and not serial flash (SPI NOR).

To use SPI NOR to save the environment instead of SD card, edit
include/configs/mx6qsabrelite.h and

- undefine CONFIG_ENV_IS_IN_MMC
- define   CONFIG_ENV_IS_IN_SPI_FLASH

The SPI driver can take as chip select the controller's chip selects
as well as an external GPIO. The LSB byte has the value of the internal
chip select, the highest (thought as 16-bit value) contains the GPIO
number.

The GPIO used on Sabre Lite is GP3:19 == 83.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Acked-by: Jason Liu <jason.hui@linaro.org>
Tested-by: Jason Liu <jason.hui@linaro.org>

include/configs/mx6qsabrelite.h

@@ -174,10 +174,22 @@
 /* FLASH and environment organization */
 #define CONFIG_SYS_NO_FLASH
 
-#define CONFIG_ENV_OFFSET              (6 * 64 * 1024)
-#define CONFIG_ENV_SIZE                        (8 * 1024)
+#define CONFIG_ENV_SIZE			(8 * 1024)
+
 #define CONFIG_ENV_IS_IN_MMC
-#define CONFIG_SYS_MMC_ENV_DEV         0
+/* #define CONFIG_ENV_IS_IN_SPI_FLASH */
+
+#if defined(CONFIG_ENV_IS_IN_MMC)
+#define CONFIG_ENV_OFFSET		(6 * 64 * 1024)
+#define CONFIG_SYS_MMC_ENV_DEV		0
+#elif defined(CONFIG_ENV_IS_IN_SPI_FLASH)
+#define CONFIG_ENV_OFFSET		(768 * 1024)
+#define CONFIG_ENV_SECT_SIZE		(8 * 1024)
+#define CONFIG_ENV_SPI_BUS		CONFIG_SF_DEFAULT_BUS
+#define CONFIG_ENV_SPI_CS		CONFIG_SF_DEFAULT_CS
+#define CONFIG_ENV_SPI_MODE		CONFIG_SF_DEFAULT_MODE
+#define CONFIG_ENV_SPI_MAX_HZ		CONFIG_SF_DEFAULT_SPEED
+#endif
 
 #define CONFIG_OF_LIBFDT