arch/powerpc: Enable powerpc64le only on CPUs that support it

Invalid configurations lead to build failures, such as trying to enable
ppc64le for the ppc970:

  http://autobuild.buildroot.net/results/fda886768fce25ccd9b52b635ff5b13da7ba2d0c/

In order to run a ppc64le userspace a kernel that runs in this mode is
required. The only CPU supported in buildroot that can boot a ppc64le
kernel is Power8, so mark all of the other 64-bit capable CPUs as not
supporting ppc64le.

This drops the comment about libc, which is true but doesn't tell the
whole story.

Signed-off-by: Joel Stanley <[email protected]>

Author: shenki

Diff for: arch/Config.in.powerpc

@@ -71,11 +71,9 @@ config BR2_powerpc_604e
 	depends on !BR2_ARCH_IS_64
 config BR2_powerpc_620
 	bool "620"
-	# No C library supports this variant on ppc64le
 	depends on !BR2_powerpc64le
 config BR2_powerpc_630
 	bool "630"
-	# No C library supports this variant on ppc64le
 	depends on !BR2_powerpc64le
 config BR2_powerpc_740
 	bool "740"
@@ -102,6 +100,7 @@ config BR2_powerpc_860
 	depends on !BR2_ARCH_IS_64
 config BR2_powerpc_970
 	bool "970"
+	depends on !BR2_powerpc64le
 	select BR2_POWERPC_CPU_HAS_ALTIVEC
 config BR2_powerpc_8540
 	bool "8540 / e500v1"
@@ -129,21 +128,25 @@ config BR2_powerpc_e6500
 	select BR2_POWERPC_CPU_HAS_ALTIVEC
 config BR2_powerpc_power4
 	bool "power4"
-	# No C library supports this variant on ppc64le
 	depends on !BR2_powerpc64le
 config BR2_powerpc_power5
 	bool "power5"
-	# No C library supports this variant on ppc64le
 	depends on !BR2_powerpc64le
+	depends on BR2_ARCH_IS_64
 config BR2_powerpc_power6
 	bool "power6"
+	depends on !BR2_powerpc64le
+	depends on BR2_ARCH_IS_64
 	select BR2_POWERPC_CPU_HAS_ALTIVEC
 config BR2_powerpc_power7
 	bool "power7"
+	depends on !BR2_powerpc64le
+	depends on BR2_ARCH_IS_64
 	select BR2_POWERPC_CPU_HAS_ALTIVEC
 	select BR2_POWERPC_CPU_HAS_VSX
 config BR2_powerpc_power8
 	bool "power8"
+	depends on BR2_ARCH_IS_64
 	select BR2_POWERPC_CPU_HAS_ALTIVEC
 	select BR2_POWERPC_CPU_HAS_VSX
 endchoice