charger: accomodate minui change

gr_text() now takes an argument requesting bold text instead of
regular.

Change-Id: I18b54f05ae4a89cb753fa5977a870f1bc827b963
diff --git a/charger/charger.c b/charger/charger.c
index 353bdf0..66ddeaf 100644
--- a/charger/charger.c
+++ b/charger/charger.c
@@ -610,7 +610,7 @@
         x = (gr_fb_width() - str_len_px) / 2;
     if (y < 0)
         y = (gr_fb_height() - char_height) / 2;
-    gr_text(x, y, str);
+    gr_text(x, y, str, 0);
 
     return y + char_height;
 }