ASoC: soc_sdw_utils: skip aux device if it is not present #8255

Job	Run time
GCC static -fanalyzer	4m 9s
GCC build arm64	24m 8s
Clang build x86_64	6m 24s
GCC build i386	17m 50s
GCC build X86_64 with W=1	3m 6s
GCC build X86_64 with W=1 allmodconfig	1m 52s
Sparse check	4m 35s
GCC build X86_64	21m 19s
GCC build arm64 allmodconfig	1m 49s
	1h 25m 12s

Provide feedback