[U-Boot] [PATCH]Drivers video correction for raspberry pi 2

Correct the black screen console of the HDMI output (Thanks to Aka) Correct an missing allocated video struct: When use a bitmap function or splash screen u-boot stop to work correctly: The panel_info.cmap is not allocated and has a NULL value. The cmap is fill at 0x000000 and all the first sector (device tree include because it’s at 0x100) is overwritten.

Patch is test on the last stable branch master.

Best regards