arm: Remove plat-tcc directory

The Telechips ARM architecture is being removed. This patch
deletes the arch/arm/plat-tcc/ folder.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Harry Sievers <hsievers@csselectronic.com>
Signed-off-by: Hans J. Koch <hjk@hansjkoch.de>