PRCM: 34XX: Add PARENT_CONTROLS_CLOCK flag to dpll5_m2_ck

This patch removes following message on dpll5_m2_ck enable and
disable:

clock.c: Enable for dpll5_m2_ck without enable code
clock: clk_disable called on independent clock dpll5_m2_ck
which has no enable_reg

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>