sc: Use current console rather than first console for mouse input

When mouse reporting feature is turned on (control sequence ^[[?1000h),
syscons sends valid mouse coordinates only for ttyv0. Applications
running on other ttys always (erroneously) get mouse coordinates from
the first tty, not from tty they actually run.

Steps to reproduce:

1. On ttyv0, run any application that uses mouse reporting feature. Make some clicks. The feature works properly.
2. Switch to another ttyv, run the application. The application receives mouse click events, but mouse position reported by syscons to the application does not match with the actual mouse position on the screen.

Expected result:
Reported mouse position should match with visible mouse position.

PR: 193339
Reviewed by: imp