monmap: pass by ref

monmap: pass by ref

CID 717039 (#1 of 1): Big parameter passed by value (PASS_BY_VALUE)
Passing parameter my_addr of type entity_addr_t (size 136 bytes) by value.

CID 717040: Big parameter passed by value (PASS_BY_VALUE)
Passing parameter a of type entity_addr_t (size 136 bytes) by value.

CID 717041: Big parameter passed by value (PASS_BY_VALUE)
Passing parameter a of type entity_addr_t (size 136 bytes) by value.

CID 717043: Big parameter passed by value (PASS_BY_VALUE)
Passing parameter a of type entity_addr_t (size 136 bytes) by value.

Signed-off-by: Sage Weil <sage@inktank.com>