esp32: Fix redefinition of BIT() macro

Esp-idf defines the BIT macro that is also defined in Zephyr's
misc/util.h.  Fix the issue by including the esp-idf headers first, so
that a check in util.h won't redefine the macro if it's already
defined.

Signed-off-by: Leandro Pereira <leandro.pereira@intel.com>