media: intel/ipu4: Change device/driver names from IPU6 to IPU4

Signed-off-by: Andreas Helbech Kleist <[email protected]>

Linux 6.6

Linux 4.15-rc1

Linux 4.14

Linux 4.14-rc8

Linux 4.14-rc7

Linux 4.14-rc6

Linux 4.14-rc5

Linux 4.14-rc4

Linux 4.14-rc3