Bluetooth: SMP: Fix not waiting for remote DHCheck

When doing LE SC pairing with Passkey Confirmation slave must wait
for remote DHCheck before doing comparison. This fix issue with
pairing as slave when passkey was first confirmed locally.

Change-Id: Iba780836341a944997adde24285b2e650b31afa1
Signed-off-by: Szymon Janc <ext.szymon.janc@tieto.com>