Metal: Fix availability for kIOMainPortDefault Remove ad hoc deprecation disables for kIOMasterPortDefault. macCatalyst kIOMainPortDefault available 15.0, less than minimum 15.6. Remove the ifdefs. Bug: angleproject:360147118 Change-Id: I2ccc08814e267984ff53275cc2886e2bfa8d4c2a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5797149 Commit-Queue: Kimmo Kinnunen <kkinnunen@apple.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Auto-Submit: Kimmo Kinnunen <kkinnunen@apple.com> Reviewed-by: Alexey Knyazev <lexa.knyazev@gmail.com>