platform/x86: intel_cht_int33fe: make a couple of local functions static

The functions cht_int33fe_check_for_max17047 and cht_int33fe_find_max17047
are local to the source and do not need to be in global scope, so make
them static.

Cleans up sparse warnings:
symbol 'cht_int33fe_check_for_max17047' was not declared. Should it be
static?
symbol 'cht_int33fe_find_max17047' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>