video: bcm2835: respect the pitch value

Depending on the firmware's video options [1] the active SDTV or
HDTV mode can yield a framebuffer with noncontiguous horizontal lines,
giving a messed up display, for both, u-boot and the loaded kernel.

Fix this by setting lcd_line_length to the pitch value of the configured
framebuffer.

[1] http://elinux.org/RPiconfig#Video_mode_options



Signed-off-by: Andre Heider <a.heider@gmail.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>