MAINTAINERS: drop Antti Palosaari

He is currently inactive (last message from him is two years ago [1]). 
His media tree [2] is also dormant (latest activity is 6 years ago), yet
his site is still online [3].

Drop him from MAINTAINERS and add CREDITS entry for him. We thank him
for maintaining various DVB drivers.

[1]: https://lore.kernel.org/all/[email protected]/
[2]: https://git.linuxtv.org/anttip/media_tree.git/
[3]: https://palosaari.fi/linux/

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Bagas Sanjaya <[email protected]>
Acked-by: Antti Palosaari <[email protected]>
Cc: Hans Verkuil <[email protected]>
Cc: Lukas Bulwahn <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Uwe Kleine-König <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

CREDITS

@@ -2944,6 +2944,14 @@ D: IPX development and support
 N: Venkatesh Pallipadi (Venki)
 D: x86/HPET
 
+N: Antti Palosaari
+E: [email protected]
+D: Various DVB drivers
+W: https://palosaari.fi/linux/
+S: Yliopistokatu 1 D 513
+S: FI-90570 Oulu
+S: FINLAND
+
 N: Kyungmin Park
 E: [email protected]
 D: Samsung S5Pv210 and Exynos4210 mobile platforms