crimson/osd/lsan_suppressions: add MallocExtension::Register

crimson/osd/lsan_suppressions: add MallocExtension::Register

```
=================================================================
==80592==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x7f5c76eb6367 in operator new(unsigned long) (/lib64/libasan.so.6+0xb6367)
    #1 0x7f5c76a2fb81 in MallocExtension::Register(MallocExtension*) (/lib64/libtcmalloc.so.4+0x2fb81)

SUMMARY: AddressSanitizer: 8 byte(s) leaked in 1 allocation(s)
```

Signed-off-by: Matan Breizman <mbreizma@redhat.com>