Bluetooth: HFP HF: Enable extended AG Error Result Code

Send standard AT+CMEE command used to enable the use of result
code +CME ERROR.

< ACL Data TX: Handle 256 flags 0x00 dlen 18           [hci0] 23.101226
      Channel: 67 len 14 [PSM 3 mode 0] {chan 0}
      RFCOMM: Unnumbered Info with Header Check (UIH) (0xef)
         Address: 0x09 cr 0 dlci 0x02
         Control: 0xef poll/final 0
         Length: 10
         FCS: 0x40
        41 54 2b 43 4d 45 45 3d 31 0d 40                 AT+CMEE=1.@
> ACL Data RX: Handle 256 flags 0x02 dlen 15           [hci0] 23.127140
      Channel: 64 len 11 [PSM 3 mode 0] {chan 0}
      RFCOMM: Unnumbered Info with Header Check (UIH) (0xef)
         Address: 0x0b cr 1 dlci 0x02
         Control: 0xff poll/final 1
         Length: 6
         FCS: 0x86
         Credits: 1
        0d 0a 4f 4b 0d 0a 86                             ..OK...

Change-Id: I246c25252440c9c973e1f90156dab44c48f02c3a
Signed-off-by: Sathish Narasimman <sathish.narasimman@intel.com>