arch/powerpc: add powerpc64le support

Technically, I don't forbid powerpcle support either, but I'm not sure that
there is any library/compiler support for that at the moment (though the hw
technically makes it possible).

powerpc64le needs glibc 2.19 and gcc 4.9. I haven't looked into the support
tools, but at least gdb 7.5 is too old (7.7.1 definitely has support).

Also make powerpc64 non-experimental. It's practically old at this point.

Signed-off-by: Cody P Schafer <dev@codyps.com>
[yann.morin.1998@free.fr: use ${target_endian_le} and ${target_bits_64}]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <64bfbbced9dd8f62e0d6.1399801945@gun>
Patchwork-Id: 347775

diff -urN uClibc-0.9.33.2~orig/Rules.mak uClibc-0.9.33.2/Rules.mak

--- uClibc-0.9.33.2~orig/Rules.mak	2012-05-15 09:20:09.000000000 +0200

+++ uClibc-0.9.33.2/Rules.mak	2012-09-24 14:09:51.092953729 +0200

@@ -226,6 +226,7 @@

 OPTIMIZATION:=

 # Use '-Os' optimization if available, else use -O2, allow Config to override

+ifneq ($(TARGET_ARCH),m68k)

 $(eval $(call check-gcc-var,-Os))

 ifneq ($(CFLAG_-Os),)

 OPTIMIZATION += $(CFLAG_-Os)

@@ -233,6 +234,7 @@

 $(eval $(call check-gcc-var,-O2))

 OPTIMIZATION += $(CFLAG_-O2)

 endif

+endif

 # Use the gcc 3.4 -funit-at-a-time optimization when available

 $(eval $(call check-gcc-var,-funit-at-a-time))

 OPTIMIZATION += $(CFLAG_-funit-at-a-time)