toolchain: add 4.6.x choice for headers

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
diff --git a/toolchain/toolchain-external/Config.in b/toolchain/toolchain-external/Config.in
index b7f9241..a037d67 100644
--- a/toolchain/toolchain-external/Config.in
+++ b/toolchain/toolchain-external/Config.in
@@ -769,6 +769,10 @@
 	    m = ( LINUX_VERSION_CODE >> 8  ) & 0xFF
 	    p = ( LINUX_VERSION_CODE >> 0  ) & 0xFF
 
+config BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_6
+	bool "4.6.x"
+	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_6
+
 config BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_5
 	bool "4.5.x"
 	select BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_5