The TRCSEQRSTEVR and TRCSEQSTR registers are not implemented if the
TRCIDR5.NUMSEQSTATE == 0. Skip accessing the registers in such cases.
Fixes: 2e1cdfe184b5 ("coresight-etm4x: Adding CoreSight ETM4x driver")
Signed-off-by: Junhao He <hejunhao3@xxxxxxxxxx>
Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>