Fix Compile Errors when using M5Stack Version 2.0.5 or newer

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This will fix the following compile errors, that occur when compiling with M5Stack Version 2.0.5 or newer in the Arduino IDE:

• 'font' defined but not used [-Werror=unused-const-variable]
• array subscript 6 is above array bounds of 'uint8_t [2]' [-Werror=array-bounds]