tools: logo: split bmp arrays from bmp_logo.h

The generated header bmp_logo.h is useful even outside common/lcd.c for
the logo dimension.  However, the problem is, the generated bmp_logo.h
cannot be included multiple times because bmp_logo_palette[] and
bmp_logo_bitmap[] are defined in the bmp_logo.h.

This patch fixes this by defining these arrays in another header
bmp_logo_data.h and in bmp_logo.h only declaring these arrays.

Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Anatolij Gustschin <agust@denx.de>