x86/of: Kill unused early_init_dt_scan_chosen_arch()

There are no callers for early_init_dt_scan_chosen_arch(), so remove it.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Link: https://lkml.kernel.org/r/20211022164642.2815706-1-robh@kernel.org