[source] kernel: fixup KARCH for powerpc64 builds

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/f28b3bb56af4cb870f5b9b8a6e5bd0b3021de837

commit f28b3bb56af4cb870f5b9b8a6e5bd0b3021de837
Author: Florian Larysch <fl at n621.de>
AuthorDate: Thu Nov 3 13:58:24 2016 +0100

    kernel: fixup KARCH for powerpc64 builds
    
    The kernel calls both ppc64 and ppc32 "powerpc", so we need to fixup
    LINUX_KARCH when building with ARCH=powerpc64.
    
    Signed-off-by: Florian Larysch <fl at n621.de>
---
 include/kernel.mk | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/kernel.mk b/include/kernel.mk
index 7674f0d..a84c755 100644
--- a/include/kernel.mk
+++ b/include/kernel.mk
@@ -85,6 +85,8 @@ else ifneq (,$(findstring $(ARCH) , armeb ))
   LINUX_KARCH := arm
 else ifneq (,$(findstring $(ARCH) , mipsel mips64 mips64el ))
   LINUX_KARCH := mips
+else ifneq (,$(findstring $(ARCH) , powerpc64 ))
+  LINUX_KARCH := powerpc
 else ifneq (,$(findstring $(ARCH) , sh2 sh3 sh4 ))
   LINUX_KARCH := sh
 else ifneq (,$(findstring $(ARCH) , i386 x86_64 ))