MAINTAINERS: Update Michael Jamet's maintainer entries

Michael Jamet is about to continue his professional journey outside of
Intel and is stepping down as maintainer of Thunderbolt/USB4 subsystem,
and the networking driver. Move him from MAINTAINERS to CREDITS.

Thank you, Michael!

Cc: Michael Jamet <[e-mail]>
Signed-off-by: Mika Westerberg <[e-mail]>

CREDITS

···
 S: RG6 2NU
 S: United Kingdom
 
+N: Michael Jamet
+E: [e-mail]
+D: Thunderbolt/USB4 driver maintainer
+D: Thunderbolt/USB4 networking driver maintainer
+
 N: Dave Jeffery
 E: [e-mail]
 D: SCSI hacks and IBM ServeRAID RAID driver maintenance

MAINTAINERS

···
 
 THUNDERBOLT DRIVER
 M:	Andreas Noever <[e-mail]>
-M:	Michael Jamet <[e-mail]>
 M:	Mika Westerberg <[e-mail]>
 M:	Yehezkel Bernat <[e-mail]>
 L:	[e-mail]
···
 F:	include/linux/thunderbolt.h
 
 THUNDERBOLT NETWORK DRIVER
-M:	Michael Jamet <[e-mail]>
 M:	Mika Westerberg <[e-mail]>
 M:	Yehezkel Bernat <[e-mail]>
 L:	[e-mail]