fix: remove old-style declarations

TF-A wants to eventually enable -Wold-style-definition globally. Convert
the rare few instances where this is still the case.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I9c450fc875cf097e6de2ed577ea3b085821c9f5e
diff --git a/plat/xilinx/versal/versal_ipi.c b/plat/xilinx/versal/versal_ipi.c
index f99af82..d821929 100644
--- a/plat/xilinx/versal/versal_ipi.c
+++ b/plat/xilinx/versal/versal_ipi.c
@@ -19,7 +19,7 @@
 #include <lib/mmio.h>
 
 /* versal ipi configuration table */
-const static struct ipi_config versal_ipi_table[] = {
+static const struct ipi_config versal_ipi_table[] = {
 	/* A72 IPI */
 	[IPI_ID_APU] = {
 		.ipi_bit_mask = IPI0_TRIG_BIT,