ARM: OMAP: board-nokia770: correct lcd name

Some time ago, the 'lcd_lph8923' device was renamed to 'lcd_mipid' but
the board-nokia770.c file was not updated accordingly, leading to not
working lcd.

This one-liner fixe the trouble.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>