MAINTAINERS: adjust SAMSUNG SOC CLOCK DRIVERS after s3c24xx support removal

Commit a4946a153cb9 ("ARM: s3c: remove all s3c24xx support") removes all
files that match the file pattern 'include/dt-bindings/clock/s3c*.h'.

Hence,  ./scripts/get_maintainer.pl --self-test=patterns complains about a
obsolete file pattern in SAMSUNG SOC CLOCK DRIVERS, as it does not match
any file in the repository after the commit above.

Remove this obsolete file entry in SAMSUNG SOC CLOCK DRIVERS.

Fixes: a4946a153cb9 ("ARM: s3c: remove all s3c24xx support")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>