env: Added support to save env to spi through Kconfig

This patch added support to enable CONFIG_ENV_SIZE, CONFIG_ENV_OFFSET
and CONFIG_ENV_SECT_SIZE through Kconfig for Zynq and Zynqmp.

Signed-off-by: Vipul Kumar <vipul.kumar@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/bitmain_antminer_s9_defconfig b/configs/bitmain_antminer_s9_defconfig
index 40bce4e..f59c767 100644
--- a/configs/bitmain_antminer_s9_defconfig
+++ b/configs/bitmain_antminer_s9_defconfig
@@ -4,6 +4,7 @@
 CONFIG_SYS_CONFIG_NAME="bitmain_antminer_s9"
 CONFIG_ARCH_ZYNQ=y
 CONFIG_SYS_TEXT_BASE=0x4000000
+CONFIG_ENV_OFFSET=0x300000
 CONFIG_SPL=y
 CONFIG_DEBUG_UART_BASE=0xe0001000
 CONFIG_DEBUG_UART_CLOCK=50000000