test: apply optimization for v4.14 kernel about changes for TLV data handling on...

test: apply optimization for v4.14 kernel about changes for TLV data handling on user-defined element set

At kernel v4.14, in initial state, elements on user-defined sets have
write-only flag. When applications write TLV data, then the elements
get readable flag and the TLV data is available. Originally TLV data
is shared by elements in the same set, thus events are generated for
all of elements in the set by the write operation.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>