Fat_zero_cluster() use fs_heap_malloc() for buffer that
is used to call fat_hwread().
Fat_hwread() must be called with IO buffer that have proper
alingment because it might use DMA.
Fix changes fs_heap_malloc() to fat_io_alloc() which uses
correct fat_dma_alloc() if CONFIG_FAT_DMAMEMORY is defined.
Signed-off-by: Ari Kimari <ari.kimari@tii.ae>
0ded247f44