minui: Fix gr_set_font() build issue on cm-13.0 tree.

- Add a fake function which fill the vendor/cm/charger/healthd_board_cm.cpp requirements.

Solve omnirom/android_bootable_recovery#84 issue.

Change-Id: Ia9bf898006da7e4f4ee6a942584fe2dd3c88f8ba

Author: nailyk-fr

minui/graphics.cpp

@@ -545,3 +545,9 @@ void gr_fb_blank(bool blank)
 {
     gr_backend->blank(gr_backend, blank);
 }
+
+void gr_set_font(__attribute__ ((unused))const char* name) {
+	//this cm function is made to change font. Don't care, just init the font:
+	gr_init_font();
+	return;
+}

minui/minui.h

@@ -51,6 +51,7 @@ void gr_text(int x, int y, const char *s, bool bold);
 void gr_texticon(int x, int y, GRSurface* icon);
 int gr_measure(const char *s);
 void gr_font_size(int *x, int *y);
+void gr_set_font(__attribute__ ((unused))const char* name);
 
 void gr_blit(GRSurface* source, int sx, int sy, int w, int h, int dx, int dy);
 unsigned int gr_get_width(GRSurface* surface);