bluetooth: Classic: l2cap: accept peer MPS larger than TX MTU

Fix L2CAP configuration negotiation failure when peer device sends
MPS value larger than its own TX MTU in the configuration request.

This issue occurs when connecting to certain devices (e.g., iPhone)
using enhanced retransmission mode with MAP or PBAP profiles. The
peer may send an MPS that exceeds the TX MTU specified in the same
L2CAP_CONFIGURATION_REQ packet.

Instead of rejecting the configuration, adjust the MPS to match the
peer's TX MTU and include the corrected value in the
L2CAP_CONFIGURATION_RSP packet. This allows the connection to proceed
while ensuring MPS stays within valid bounds.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>