arm: socfpga: disable CONFIG_SPL_WDT for gen5 and a10

These boards don't have a watchdog enabled in SPL, so make sure
CONFIG_SPL_WDT is not enabled.

Fixes: commit 6874cb72204f ("watchdog: Split WDT from SPL_WDT")

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
diff --git a/configs/socfpga_sr1500_defconfig b/configs/socfpga_sr1500_defconfig
index 89349ce..092347a 100644
--- a/configs/socfpga_sr1500_defconfig
+++ b/configs/socfpga_sr1500_defconfig
@@ -57,3 +57,4 @@
 CONFIG_DM_RESET=y
 CONFIG_SPI=y
 CONFIG_CADENCE_QSPI=y
+# CONFIG_SPL_WDT is not set