clear display struct during init

src/lcd/lcdbuf.c

@@ -15,6 +15,7 @@ void LcdBuffer_Init(struct LcdBuffer *self, const struct LcdBuf_CGROM_Entry *cgr
     assert(cgrom);
     assert(custom_symbols);
 
+    memset(self, 0, sizeof(struct LcdBuffer));
     LcdBuffer_Clear(self);
     self->cgrom = cgrom;
     self->custom_symbols = custom_symbols;