tools/valgrind: Add suppression for __btd_log_init

tools/valgrind: Add suppression for __btd_log_init

valgrind seems to treat every bind to PF_BLUETOOTH as an RFCOMM socket
causing the following false positives:

Syscall param socketcall.bind(my_addr.rc_bdaddr) points to uninitialised byte(s)
   at 0x52728A7: bind (in /usr/lib64/libc-2.21.so)
   by 0x4045B1: logging_open (log.c:76)
   by 0x4045B1: __btd_log_init (log.c:298)
   by 0x402823: main (test-avctp.c:278)
 Address 0xffefffcb6 is on thread 1's stack
 in frame #1, created by __btd_log_init (log.c:290)
 Uninitialised value was created by a stack allocation
   at 0x404490: __btd_log_init (log.c:290)

Syscall param socketcall.bind(my_addr.rc_channel) points to uninitialised byte(s)
   at 0x52728A7: bind (in /usr/lib64/libc-2.21.so)
   by 0x4045B1: logging_open (log.c:76)
   by 0x4045B1: __btd_log_init (log.c:298)
   by 0x402823: main (test-avctp.c:278)
 Address 0xffefffcb8 is on thread 1's stack
 in frame #1, created by __btd_log_init (log.c:290)
 Uninitialised value was created by a stack allocation
   at 0x404490: __btd_log_init (log.c:290)