FWU: Pass client cookie to FWU_SMC_UPDATE_DONE

The current FWU_SMC_UPDATE_DONE implementation incorrectly passes
an unused framework cookie through to the 1st argument in the
platform function `bl1_plat_fwu_done`. The intent is to allow
the SMC caller to pass a cookie through to this function.

This patch fixes FWU_SMC_UPDATE_DONE to pass x1 from the caller
through to `bl1_plat_fwu_done`. The argument names are updated
for clarity.

Upstream platforms currently do not use this argument so no
impact is expected.

Change-Id: I107f4b51eb03e7394f66d9a534ffab1cbc09a9b2
diff --git a/plat/common/plat_bl1_common.c b/plat/common/plat_bl1_common.c
index aee9440..e637aaf 100644
--- a/plat/common/plat_bl1_common.c
+++ b/plat/common/plat_bl1_common.c
@@ -69,7 +69,7 @@
 	return &bl2_img_desc;
 }
 
-__dead2 void bl1_plat_fwu_done(void *cookie, void *rsvd_ptr)
+__dead2 void bl1_plat_fwu_done(void *client_cookie, void *reserved)
 {
 	while (1)
 		wfi();