btm_sec: p_name fails matching security records

When doing a comparison on p_name that is passed in against
the p_name in the struct will never match if the passed in
name is >= 21 characters.  This is due to the strlcpy replacing
the last character with a null termination character.

Without this patch, you will observe 2 security records for
"Android Network Acce" (which is supposed to be "Android Network Access Point")

BTM_SEC_SERVCE_NAME_LEN = 21

                                                    21
passed in: |A|n|d|r|o|i|d| |N|e|t|w|o|r|k| |A|c|c|e|s|s| |P|o|i|n|t|
           ---------------------------------------------------------
structval: |A|n|d|r|o|i|d| |N|e|t|w|o|r|k| |A|c|c|e|\0|

Bug: 34707848
Test: Compile, Manual
Change-Id: I24e0204d8faf54545c7b720a0fbc6765db9a1295