hostapd: Remove add-sysroot-to-gcc.patch

The patch has not been available in the 2.4 version form and thus the
recipe was unbuildable.

Fix by removing the patch file, which is unused, and the reference for
it from the recipe.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>