valgrind: Fix powerpc64le arch config name

buildroot references powerpc64 little endian as "powerpc64le" and not
"powerpc64el". The typo in the supported architectures list caused this
package to be unavailable for powerpc64 little endian.

Signed-off-by: Erico Nunes <erico.nunes@datacom.ind.br>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/valgrind/Config.in

@@ -2,7 +2,7 @@ config BR2_PACKAGE_VALGRIND
 	bool "valgrind"
 	depends on BR2_ARM_CPU_ARMV7A || BR2_i386 || \
 		   BR2_mips || BR2_mipsel || BR2_mips64 || BR2_mips64el || \
-		   BR2_powerpc || BR2_powerpc64 || BR2_powerpc64el || \
+		   BR2_powerpc || BR2_powerpc64 || BR2_powerpc64le || \
 		   BR2_x86_64
 	help
 	  Tool for debugging and profiling Linux programs.