Keyguard: don't refresh ui when screen off

KeyguardStatusView is doing refresh all the time,
which cause high power when screen off.

Change-Id: Ifabdde4419a23e919cd52fe77e78ec3160575af1
Fixed incorrect calculation of dirty invalidation area

Padding was already taken into consideration before calling
invalidateDrawable in ProgressBar.

Change-Id: I75f25b0b7ee87d394422c58888ed3a1cca5d06a8