PCI: imx6: Remove space before tabs

Remove space before tabs to fix the following checkpatch
warning:

WARNING: please, no space before tabs
+^Icase IMX6QP: ^I^I/* FALLTHROUGH */$
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>