botan: add type to BR2_PACKAGE_BOTAN_ARCH_SUPPORTS option

Commit 1737af367993326ee47e847bd755806c8a78ced8 ('botan: limit to
supported CPU architectures') introduced the
BR2_PACKAGE_BOTAN_ARCH_SUPPORTS with a default value, but forgot to
define a type, which leads to a kconfig warning:

  package/botan/Config.in:1:warning: config symbol defined without type

This commit fixes that by properly setting the type.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/botan/Config.in

@@ -1,4 +1,5 @@
 config BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
+	bool
 	default y if BR2_arm || BR2_armeb || BR2_i386 || BR2_m68k    || \
 		BR2_mips || BR2_mipsel || BR2_mips64 || BR2_mips64el || \
 		BR2_powerpc || BR2_powerpc64 || BR2_sparc || BR2_sh  || \