cxgb4: fix adapter crash due to wrong MC size

In the absence of MC1, the size calculation function
cudbg_mem_region_size() was returing wrong MC size and
resulted in adapter crash. This patch adds new argument
to cudbg_mem_region_size() which will have actual size
and returns error to caller in the absence of MC1.

Fixes: a1c69520 ("cxgb4: collect MC memory dump")
Signed-off-by: Vishal Kulkarni <vishal@chelsio.com&gt;">
Signed-off-by: David S. Miller <davem@davemloft.net>