lcd: refactor lcd console stuff into its own file

common/lcd.c is a mix of code portions that do different but related
things. To improve modularity, the various code portions should be split
into their own modules. Separate lcd console code into its own file.

Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>