rockchip: rk3566-pinetab2: Fix reading FIT from SPI flash

The SF_DEFAULT_SPEED Kconfig option got lost during merge and this
prevent reading FIT from SPI flash.

Restore the SF_DEFAULT_SPEED option to fix this.

Fixes: 8a94c376f6cb ("rockchip: Use common bss and stack addresses on RK356x")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/pinetab2-rk3566_defconfig b/configs/pinetab2-rk3566_defconfig
index edeb1d8..525a002 100644
--- a/configs/pinetab2-rk3566_defconfig
+++ b/configs/pinetab2-rk3566_defconfig
@@ -4,6 +4,7 @@
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_SPL_GPIO=y
 CONFIG_NR_DRAM_BANKS=2
+CONFIG_SF_DEFAULT_SPEED=24000000
 CONFIG_SF_DEFAULT_MODE=0x1000
 CONFIG_DEFAULT_DEVICE_TREE="rk3566-pinetab2-v2.0"
 CONFIG_ROCKCHIP_RK3568=y