arm: socfpga: Allow boards to define a custom environment size

This patch makes it possible that boards can define a board-specific env
size. This is used by the SR1500 SoCFPGA board port.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Chin Liang See <clsee@altera.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: Marek Vasut <marex@denx.de>

include/configs/socfpga_common.h

@@ -284,7 +284,9 @@ unsigned int cm_get_qspi_controller_clk_hz(void);
 #define CONFIG_SYS_CONSOLE_IS_IN_ENV
 #define CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
 #define CONFIG_SYS_CONSOLE_ENV_OVERWRITE
+#if !defined(CONFIG_ENV_SIZE)
 #define CONFIG_ENV_SIZE			4096
+#endif
 
 /* Environment for SDMMC boot */
 #if defined(CONFIG_ENV_IS_IN_MMC) && !defined(CONFIG_ENV_OFFSET)