Update size estimates in the Makefile

Update size estimates in the Makefile

MIDI_ENABLE = no

   text    data     bss     dec     hex filename
      0   17080       0   17080    42b8 satan_midi.hex

MIDI_ENABLE = yes
MIDI_BASIC undefined
MIDI_ADVANCED undefined

   text    data     bss     dec     hex filename
      0   19494       0   19494    4c26 satan_midi.hex

      +2414 bytes (vs. MIDI_ENABLE = no)

MIDI_ENABLE = yes
      0   20846       0   20846    516e satan_midi.hex

      +1352 bytes (vs. MIDI_ENABLE = yes, MIDI_BASIC off, MIDI_ADVANCED
off)

MIDI_ENABLE = yes
#define MIDI_BASIC
#define MIDI_ADVANCED

   text    data     bss     dec     hex filename
      0   21292       0   21292    532c satan_midi.hex

      +1798 bytes (vs. MIDI_ENABLE = yes, MIDI_BASIC off, MIDI_ADVANCED
off)

Conclusion:
    +2400 to 4200, depending on config