[media] s5p-tv: Don't ignore return value of regulator_bulk_enable() in hdmi_drv.c

This patch fixes following compilation warning:
 CC [M]  drivers/media/platform/s5p-tv/hdmi_drv.o
drivers/media/platform/s5p-tv/hdmi_drv.c: In function ‘hdmi_resource_poweron’:
drivers/media/platform/s5p-tv/hdmi_drv.c:583:23: warning: ignoring return value
 of ‘regulator_bulk_enable’, declared with attribute warn_unused_result

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>