Mat2057 fix

fixes compiler warnings,
completes the definition of  "struct l2cap_conn"
updates the Makefile in arch/arm/boot/compressed/
adds a definition for VEN_IOCTL_SET_SPS_PPS_FOR_IDR
sets CONFIG_FRAME_WARN to 2048 as a workaround to compile

The kernel now successfully builds with GCC 4.7 and GCC 4.4 but I get a blank screen (and not even a boot logo)