video: tegra: hdmi: make clock_refcount atomic

video: tegra: hdmi: make clock_refcount atomic

remove clock_refcount_lock mutex variable in tegra_hdmi
structure as it is not significant and make clock_refcount
variable atomic. Handle clock_refcount properly in
tegra_hdmi_get() and tegra_hdmi_put().

Bug 200132061

Change-Id: I21eff40e0c2884ca1f7bcac692ac23b32319f6fb
Signed-off-by: Santosh Reddy Galma <galmar@nvidia.com>
Reviewed-on: http://git-master/r/785977
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Venu Byravarasu <vbyravarasu@nvidia.com>