Revert "PCI: imx6: Skip controller_id generation logic for i.MX7D"

This reverts commit 2a12efc5 which is
commit f068ffdd upstream.

This is a backport mistake.

Deleting "IMX7D" here skips more than just controller_id logic. It skips
reset assignments too, which causes:

 imx6q-pcie 33800000.pcie: PCIe PLL lock timeout

In my case, in addition to broken PCIe, kernel boot hangs entirely.

This isn't a problem upstream because before this, they moved the rest of
the code out of the switch case.

Signed-off-by: Ryan Matthews <ryanmatthews@fastmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>