Removed C-style casts

In c++ code would be cleaner to use
c++ retinterpret cast instead of old
c-style notation

Change-Id: Ibeef5e0c374addf108c0a8876a6be45063d8e396
diff --git a/ui.cpp b/ui.cpp
index a796461..9194ae3 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -240,7 +240,7 @@
 }
 
 void* RecoveryUI::time_key_helper(void* cookie) {
-    key_timer_t* info = (key_timer_t*) cookie;
+    key_timer_t* info = static_cast<key_timer_t*>(cookie);
     info->ui->time_key(info->key_code, info->count);
     delete info;
     return nullptr;