[4.4] Backport request: powerpc: Fix compiling a BE kernel with a powerpc64le toolchain

Dear stable team

Please backport the following patches.

Commits:

- 164af597ce945751e2dcd53d0a86e84203a6d117
   ("powerpc/Makefile: Use cflags-y/aflags-y for setting endian options")

- 4dc831aa88132f835cefe876aa0206977c4d7710
   ("powerpc: Fix compiling a BE kernel with a powerpc64le toolchain")

Stable tree targeted: 4.4 (applies cleanly)

Justification: This fixes the build when attempting to compile a BE 
powerpc kernel using a bi-endian toolchain that defaults to LE, which is 
a common setup.

I have tested that these patches apply cleanly and appear to rectify the 
build failure on my machine.


Thanks,
-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@linux.ibm.com             IBM Australia Limited