arm64: configs: add redhat_defconfig

This config boots sa8540p-adp-ride.dtb from this branch, with some
splats as shown:

    [  244.034367] INFO: task kworker/0:0H:8 blocked for more than 123 seconds.
    [  244.041246]       Not tainted 6.0.0-rc7-next-20220930+ #1
    [  244.046789] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    [  244.054825] task:kworker/0:0H    state:I stack:0     pid:8     ppid:2      flags:0x00000008
    [  244.063391] Workqueue:  0x0 (kblockd)
    [  244.067147] Call trace:
    [  244.069658]  __switch_to+0xb0/0xe0
    [  244.073152]  __schedule+0x1d8/0x500
    [  244.076739]  schedule+0x54/0xe0
    [  244.079974]  worker_thread+0x210/0x510
    [  244.083827]  kthread+0xcc/0xd0
    [  244.086962]  ret_from_fork+0x10/0x20

Signed-off-by: Andrew Halaney <ahalaney@redhat.com>