ARM: at91: add missing uart clocks DT entries for sama5d3

Add clocks to clock lookup table for uart DT entries.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>

Conflicts:
	arch/arm/mach-at91/include/mach/sama5d3.h
Merge branch 'at91-3.10-trunk/v3.10_base+fixes' into linux-3.10-at91