buildroot

x264: needs madvise(), disable for bfin external toolchain

x264 uses madvise() which is not available in the bfin external toolchain.

Fixes:
http://autobuild.buildroot.net/results/837/837fd5a63d59b5c65818ec005a565cb7741a1cdd/

[Peter: Issue is specific to bfin toolchain, so only disable for that one]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>