Fixed possible NULL pointer reference in nlsml_instance_swi_suppress() when the instance element is empty.
Fixed possible NULL pointer reference in nlsml_instance_swi_suppress() when the instance element is empty.

AaronZhangL/unimrcp-1,unispeech/unimrcp,AaronZhangL/unimrcp-1,unispeech/unimrcp,AaronZhangL/unimrcp-1,unispeech/unimrcp