arm64: zynqmp: Change bl2_plat_get_bl31_params() guarding

It was protected just for SPL_OS_BOOT but this function is only called when
SPL_ATF is enabled that's why change macro name.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/mach-zynqmp/handoff.c b/arch/arm/mach-zynqmp/handoff.c
index 64e5320..7d7ab9d 100644
--- a/arch/arm/mach-zynqmp/handoff.c
+++ b/arch/arm/mach-zynqmp/handoff.c
@@ -65,7 +65,7 @@
 	struct xfsbl_partition partition[FSBL_MAX_PARTITIONS];
 };
 
-#ifdef CONFIG_SPL_OS_BOOT
+#ifdef CONFIG_SPL_ATF
 struct bl31_params *bl2_plat_get_bl31_params(uintptr_t bl32_entry,
 					     uintptr_t bl33_entry,
 					     uintptr_t fdt_addr)