ltrace: disable on mips/mipsel

ltrace currently doesn't build on mips/mipsel, and it's an upstream
issue that has been reported. Until it get fixed, let's disable ltrace
for mips/mipsel.

Fixes:

  http://autobuild.buildroot.org/results/43a/43a8fc7075f52eab74ebfee4c9f25dd2b886e75e/

Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/ltrace/Config.in

@@ -1,6 +1,10 @@
 config BR2_PACKAGE_LTRACE
 	bool "ltrace"
-	depends on (BR2_i386 || BR2_arm || BR2_mips || BR2_mipsel \
+	# ltrace normally has mips/mipsel support, but it's currently
+	# broken (error: 'struct ltelf' has no member named
+	# 'relplt_count'). Issue reported upstream at
+	# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=756764.
+	depends on (BR2_i386 || BR2_arm \
 		|| BR2_powerpc || BR2_sparc || BR2_x86_64)
 	select BR2_PACKAGE_LIBELF
 	select BR2_PACKAGE_ELFUTILS