Prevent LE CoC from dropping data when remote MPS>8087

When using LE Coc through Java socket, one can read MPS from
getMaxTransmitPacketSize(). If this value is bigger than
local device L2CAP_MAX_SDU_LENGTH, data sent to remote will be
truncated. This patch fixes that by using properly big buffer for
receiving data from socket on native side.

Test: connect with device with MPS bigger than MPS, alternatively set
L2CAP_MAX_SDU_LENGTH to i.e. 30 on device during test and try to write
"remote MPS" of bytes to remote device.
Bug: 68359837
Change-Id: I02bef80f0dd0f0d6850704ac7787c5f3f5b9b3ab