[source] lantiq: fix pci with kernel 4.9

[LEDE Commits]

mkresin pushed a commit to source.git, branch master:
https://git.lede-project.org/e4c53c751e5f928ee8d6494981e691f6da8ecd06

commit e4c53c751e5f928ee8d6494981e691f6da8ecd06
Author: Mathias Kresin <dev at kresin.me>
AuthorDate: Fri Mar 10 22:46:30 2017 +0100

    lantiq: fix pci with kernel 4.9
    
    Commit 23dac14d058f ("MIPS: PCI: Use struct list_head lists") changed
    the controller list from reverse to straight order. Use the last entry
    in the controller list to get the fist conroller of the system.
    
    Signed-off-by: Mathias Kresin <dev at kresin.me>
---
 .../linux/lantiq/patches-4.9/0001-MIPS-lantiq-add-pcie-driver.patch  | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/linux/lantiq/patches-4.9/0001-MIPS-lantiq-add-pcie-driver.patch b/target/linux/lantiq/patches-4.9/0001-MIPS-lantiq-add-pcie-driver.patch
index 59d29d8..16d3f55 100644
--- a/target/linux/lantiq/patches-4.9/0001-MIPS-lantiq-add-pcie-driver.patch
+++ b/target/linux/lantiq/patches-4.9/0001-MIPS-lantiq-add-pcie-driver.patch
@@ -4143,7 +4143,7 @@ Signed-off-by: John Crispin <blogic at openwrt.org>
 +
 --- a/arch/mips/pci/pci-legacy.c
 +++ b/arch/mips/pci/pci-legacy.c
-@@ -300,3 +300,30 @@ char *__init pcibios_setup(char *str)
+@@ -300,3 +300,31 @@ char *__init pcibios_setup(char *str)
  		return pcibios_plat_setup(str);
  	return str;
  }
@@ -4164,7 +4164,8 @@ Signed-off-by: John Crispin <blogic at openwrt.org>
 +    int bus_nr = 0;
 +    struct pci_controller *hose;
 +
-+    hose = list_first_entry_or_null(&controllers, struct pci_controller, list);
++    if (!list_empty(&controllers))
++        hose = list_last_entry(&controllers, struct pci_controller, list);
 +
 +    if (hose != NULL) {
 +        if (hose->bus != NULL) {