linux: Release 4.4.15-openpower1

New patches:
 - powerpc/boot: Add OPAL console to epapr wrappers
 - net/mlx5: Add pci shutdown callback, for kexec support
 - tty/hvc: Use IRQF_SHARED for OPAL hvc consoles
 - tty/hvc: Use opal irqchip interface if available

Reworked due to upstream fixes:
 - xhci: do not halt the secondary HCD

Superseded by upstream fixes:
 - Revert "usb: xhci: stop everything on the first call to xhci_stop"
 - xhci: do not halt the secondary HCD

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/barreleye_defconfig b/openpower/configs/barreleye_defconfig
index 57a98c8..580545e 100644
--- a/openpower/configs/barreleye_defconfig
+++ b/openpower/configs/barreleye_defconfig
@@ -42,7 +42,7 @@
 BR2_ROOTFS_POST_BUILD_SCRIPT="../openpower/scripts/fixup-target-var"
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.4.14"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.4.15"
 BR2_KERNEL_HEADERS_4_4=y
 BR2_BINUTILS_VERSION_2_26_X=y
 BR2_LINUX_KERNEL_PATCH="$(BR2_EXTERNAL)/linux"