Treat KEY_ENTER the same as KEY_POWER in the pager.

Our long-press UI sends KEY_ENTER for long presses, which the long-press
UI treats as equivalent to KEY_POWER in the regular UI. So anywhere we accept
KEY_POWER we should accept KEY_ENTER too.

Change-Id: I99d376c961887043cf02037c26d000c8ba4d66f9