msm_fb: hdmi: Proper switching of switch device

Switch device used to tell userspace about HDMI connection
needs to be enabled when:
1. HPD connect
2. Authentication successful

And disable when:
1. HPD disconnect
2. Authentication failed

Change-Id: I8d4529fa2335ec1b2dc1196e57e3c8bad7d6b657
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>