iopsys-ramips: enable kernel tracing

Enable kernel tracing.

Example of usage:
root@iopsys:/tmp# trace-cmd record -e cfg80211 -e mac80211
Hit Ctrl^C to stop recording

CCPU0 data recorded at offset=0xed000
    36864 bytes in size
CPU1 data recorded at offset=0xf6000
    0 bytes in size
CPU2 data recorded at offset=0xf6000
    0 bytes in size
CPU3 data recorded at offset=0xf6000
    32768 bytes in size

root@iopsys:/tmp# trace-cmd report

Signed-off-by: Janusz Dziedzic <janusz.dziedzic@iopsys.eu>