[firmware] sim_switch + wwan_perst: Don't re-initialize

The logic to detect if the respective module is already initialized
or not was broken.  When performing initialization, we of course need
to set initialized=1.

firmware/libboard/qmod/source/wwan_perst.c

@@ -109,5 +109,6 @@ int wwan_perst_init(void)
 	perst2.timer.data = (void *) &perst2;
 	num_perst++;
 #endif
+	initialized = 1;
 	return num_perst;
 }