Revert "wil6210: use INTX interrupt by default"

This reverts commit 1ea1f3f5.
The workaround is no longer needed since a proper fix got
merged that avoids turning off CPUSS AHB clock during LPM state.

Change-Id: Ia7386ee5c8432419f5c7a4c15db4ab32b24815de
Signed-off-by: Lior David <liord@codeaurora.org>