loader: Fix cast warning

Fix a cast warning found in loader.c.

Change-Id: Ie39e84ce8f050a2655c2ad3a1a146dda17c15bf9
diff --git a/loader/loader.c b/loader/loader.c
index 4dda59a..184809b 100644
--- a/loader/loader.c
+++ b/loader/loader.c
@@ -4475,7 +4475,7 @@
                 loader_set_dispatch((void *)&inst->phys_devs_term[idx],
                                     inst->disp);
                 inst->phys_devs_term[idx].this_icd = phys_devs[i].this_icd;
-                inst->phys_devs_term[idx].icd_index = i;
+                inst->phys_devs_term[idx].icd_index = (uint8_t)(i);
                 inst->phys_devs_term[idx].phys_dev = phys_devs[i].phys_devs[j];
                 if (idx < copy_count) {
                     pPhysicalDevices[idx] =