spl: Kconfig: Record proper dependency for SPL_ATF

ATF support was all the time based on FIT image support but this dependency
is not recorded anywhere.
For !SPL_FIT && SPL_ATF there is compilation error:
common/spl/spl.c: In function 'board_init_r':
common/spl/spl.c:689:26: error: 'struct spl_image_info' has no member named 'fdt_addr'
  689 |   spl_fixup_fdt(spl_image.fdt_addr);

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 6e31d75..807b1dc 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -1271,7 +1271,7 @@
 
 config SPL_ATF
 	bool "Support ARM Trusted Firmware"
-	depends on ARM64
+	depends on ARM64 && SPL_FIT
 	help
 	  ATF(ARM Trusted Firmware) is a component for ARM AArch64 which
 	  is loaded by SPL (which is considered as BL2 in ATF terminology).