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

screen_ui.cpp

@@ -539,7 +539,7 @@ void ScreenRecoveryUI::ShowFile(FILE* fp) {
             while (show_prompt) {
                 show_prompt = false;
                 int key = WaitKey();
-                if (key == KEY_POWER) {
+                if (key == KEY_POWER || key == KEY_ENTER) {
                     return;
                 } else if (key == KEY_UP || key == KEY_VOLUMEUP) {
                     if (offsets.size() <= 1) {