drm/gma500: Remove runtime_allowed dead code in psb_unlocked_ioctl()

runtime_allowed is initialized to 0, so the runtime_allowed == 1 condition
is never true making this dead code. Remove it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220909115646.99920-3-hdegoede@redhat.com