[PATCH] powerpc: e500: Fix compilation with gcc e500 compiler

[Pali Rohár]

gcc e500 compiler does not support -mcpu=powerpc option. When it is
specified then gcc throws compile error:

  gcc: error: unrecognized argument in option ‘-mcpu=powerpc’
  gcc: note: valid arguments to ‘-mcpu=’ are: 8540 8548 native

So do not set -mcpu=powerpc option when CONFIG_E500 is set. Correct option
-mcpu=8540 for CONFIG_E500 is set few lines below in that Makefile.

Signed-off-by: Pali Rohár <pali at kernel.org>
Cc: stable at vger.kernel.org
---
 arch/powerpc/Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index eb541e730d3c..87f9f29ac9d2 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -22,11 +22,16 @@ ifdef CONFIG_PPC32
 # or platform code sets later on the command line, but they are needed
 # to set a sane 32-bit cpu target for the 64-bit cross compiler which
 # may default to the wrong ISA.
+# Never set -mcpu=powerpc option for gcc e500 compiler because this
+# option is unsupported and throws error. The correct option for
+# CONFIG_E500 is -mcpu=8540 and it is set few lines below.
+ifndef CONFIG_E500
 KBUILD_CFLAGS		+= -mcpu=powerpc
 KBUILD_AFLAGS		+= -mcpu=powerpc
 endif
 endif
 endif
+endif
 
 ifdef CONFIG_PPC_BOOK3S_32
 KBUILD_CFLAGS		+= -mcpu=powerpc
-- 
2.20.1