[YM2413] Drums instruments apply the fixed pitch to only the channel it's played on

[freq-mod]

doorintosummer.zip - the module that showcases the problem. To replicate:

1. Load a module
2. Go into pattern 04
3. Play the song
4. Snare and Kick will play, together with other channels, hi-hat will not. Drums instrument enabled, fixed frequency flag turned on

[freq-mod]

Actually, issue is two-fold:

1. The logic for fetching channel state from previous patterns when playing from the middle of the song isn't taking drum mode into account
2. Drums instruments aren't applying the fixed pitch to all channels at once, only the channel it's played on (this causes the cymbal and hihat to sound wrong until you play a note on the other channel)

[freq-mod]

OK, so the main issue is fixed, but looks like fixed frequency is still ignored (point 2 of the comment)

[tildearrow]

Pitches are now set properly, but still not on every channel.

[tildearrow]

forceIns() now fixed

[tildearrow]

Added an option to apply fixed freq to all drums at once.