ARM: at91: add AT91_SAM9_TIME entry to select at91sam926x_time.c compilation

No more associate at91sam926x_time.c compilation with SOC_AT91SAM9 entry since
SAMA5D3 devices will use this driver too.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>