Input: iqs7222 - avoid sending empty SYN_REPORT events

Add a check to prevent sending undefined events, which ultimately
map to SYN_REPORT.

Fixes: e505edae ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Link: https://lore.kernel.org/r/20220908131548.48120-7-jeff@labundy.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>