configs/qemu_sh4*: rename back the linux config file to linux-4.9.config

configs/qemu_sh4*: rename back the linux config file to linux-4.9.config

In commit 28d97609b25cb534a55b6cf6b1945428e817c54a ("configs/qemu:
bump to the latest kernel version") updated most qemu defconfigs to
use Linux 4.11. However, for the SH4 configurations, Linux 4.9 was
kept, because 4.11 apparently has an issue.

Unfortunately, while the defconfigs for SH4 were unchanged, the Linux
kernel configuration file was renamed from linux-4.9.config to
linux-4.11.config.

This commit renames the Linux configuration files back to their
previous name, linux-4.9.config, matching what the Qemu SH4 defconfigs
specify.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>