MALLOC_CAP_DMA for PSRAM

[mcbp223]

Hi, I am testing the sprite examples with WT32-SC01-Plus, forcing the allocation from PSRAM by setting sprites[i].setPsram(true); just before calling sprites[i].createSprite(...);.
There's a speed increase when adding | MALLOC_CAP_DMA to heap_alloc_psram(...), in file lgfx/v1/platforms/esp32/common.hpp at line 81, can you please include if no adverse side effects.

EDIT: sorry in my test case the allocation failed and it went to the branch that calls heap_alloc_dma(length);, which is in internal SRAM, so please ignore.