iwlwifi: pcie: apply no-reclaim logic only to group 0

When applying no-reclaim logic to commands other than the group
zero for legacy commands, commands such as 0x1c (TX_CMD in group
0) can't be used in any other group. Fix that by applying this
logic only for group 0 - it's not and should never be needed for
any other groups.

Reported-by: Sharon Dvir <sharon.dvir@intel.com>
Reported-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>