common/lcd_console: cleanup lcd_drawchars/lcd_putc_xy

the capability of drawing some *str with count from lcd_drawchars is unnary.
It is always called from lcd_putc_xy with one character of and count = 1.

So we simply rename lcd_drawchars into lcd_putc_xy and remove the loops inside.

Signed-off-by: Hannes Petermaier <hannes.petermaier@br-automation.com>
Signed-off-by: Hannes Petermaier <oe5hpm@oevsv.at>
Acked-by: Nikita Kiryanov <nikita@compulab.co.il>