HFP: Check AT command buffer boundary during parsing

HFP: Check AT command buffer boundary during parsing

* add p_end parameter to tBTA_AG_AT_CMD_CBACK, bta_ag_at_hsp_cback
  and bta_ag_at_hfp_cback to indicate effective data range of p_arg
* add checks for buffer copy overflow in bta_ag_at_hsp_cback and
  bta_ag_at_hfp_cback
* add packet legnth checks with p_end in bta_ag_parse_cmer
* add packet length checks with p_end in bta_ag_parse_bac

Bug: 112860487
Test: testplans/details/218593/3975
Change-Id: I6bbbc2ba29ad025c7d3ba023d8191af6a11c4aa9
(cherry picked from commit 28ddbe904bd15c9636063f5431a9360d8e9df8b9)