[platform][qemu-virt-riscv] switch to dlmalloc as default heap
[platform][qemu-virt-riscv] switch to dlmalloc as default heap

miniheap is really not set up for large memory machines.

littlekernel/lk,hollanderic/lkstuff,littlekernel/lk,hollanderic/lkstuff,hollanderic/lkstuff,littlekernel/lk,hollanderic/lkstuff,littlekernel/lk