cxgb4: collect on-chip memory information

Collect memory layout of various on-chip memory regions.  Move code
for collecting on-chip memory information to cudbg_lib.c and update
cxgb4_debugfs.c to use the common function.  Also include
cudbg_entity.h before cudbg_lib.h to avoid adding cudbg entity
structure forward declarations in cudbg_lib.h.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>