PCI/VGA: Simplify vga_arbiter_notify_clients()

In vga_arbiter_notify_clients(), "new_state" was computed during every loop
iteration even though it doesn't depend on anything that changes during the
loop.   Move the computation outside the loop.

[bhelgaas: drop renames that obscure the purpose, commit log]
Link: https://lore.kernel.org/r/20230808223412.1743176-6-sui.jingfeng@linux.dev


Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>