Enable build of EMEV2 and KZM9D DT Reference in
case of ARCH_MULTIPLATFORM and ARCH_SHMOBILE_MULTI.

IS_ENABLED() is leaves the clock-emev2.c file out
in case of COMMON_CLK=y.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>