When kernel panic, irq will be disabled, when dump Rome
firmware, dma buffer is malloced and freed every time
hif_diag_read_mem is called to dump 20K mem, dma_free_attrs is
called 100 times for 2M mem dump, WARN_ON(irqs_disabled())
will printk stack about 100 times in short time, watchdog bite.
Fix: Change dma mem malloc size from 20KB to 256KB, then only
malloc/free less than 10 times totally when dump Rome firmware.
Change-Id: I803b2cd30a1c6cdc1ce8f8f1073cdb6c17b650af
CRs-Fixed: 2693690
da8f2bf948