miyoo: Use low memory configuration

[jSTE0]

Use the same not storing files in memory, no preload digital sounds and
small cache configuration as the RS-90 as it also only has 32MB RAM.
Also remove irrelevant build flags.

@phcoder I removed the ecwolf-preload-digisound config option from RS-90 as well since it's hard-coded as disabled.

[phcoder]

Just 32 MiB of RAM doesn't warrant using this low-memory configuration by default. It comes at drawbacks of freezes for few seconds when losing new sounds. Did you expérience any specific problem? On my PowKiddy it runs fine

[jSTE0]

I didn't notice any pauses either way (over the first 3 levels of Wolf3D shareware at least). Without this patch, memory consumption (as displayed in the notification bar) reached 26MB out of 27MB available. With this, it starts at about 16MB. I figured this was better than potentially using swap (it has a 256MB swap partition).

[phcoder]

Swap is likely preferable to fully evicting samples altogether. Reloading samples requires decompressing on top of I/O. RS90 problem is because of its reliance on zswap and that music sample break zswap assumption that memory is well compressible by generic compression algorithms (samples are not). zswap effectively reduces RAM on RS90 for ecwolf case instead of increasing it

[jSTE0]

I see, I didn't realise the RS-90 uses zswap (I don't have one).
For Miyoo, I think it's still worth hardcoding store_files_in_memory = false as that's the default anyway and there isn't enough memory left to turn it on. For preload_digital_sounds that can be left configurable (and leave the default as true) but limit_sound_cache_size should use the same values as RS-90. Would that be better?

[jSTE0]

@phcoder Any other objections to the PR? It works for me, increase the resolution to 320x240 and it still maintains 35fps.

[LibretroAdmin]

Hi there @phcoder , any final feedback on this?