[COMMANDS] Add blank, fillrect and a built-in logo framebuffer commands.

The following commands have been added for the framebuffer:
  - blank <fb_name> <value>
    . fb_name: The name of the framebuffer
    . value:   The integer value corresponding to the requested blanking state
               (FB_BLANK_POWERDOWN, FB_BLANK_VSYNC_SUSPEND,
                FB_BLANK_HSYNC_SUSPEND, FB_BLANK_NORMAL, FB_BLANK_UNBLANK).

  - fillrect <fb_name> <x> <y> <w> <h> <c> [<rop>]
    . fb_name: The name of the framebuffer
    . x:       The rectangle horizontal position.
    . y:       The rectangle vertical position.
    . w:       The rectangle width.
    . h:       The rectangle height.
    . rop:     The fill operation type (optional).

  - logo <fb_name> <x> <y> <w> <h>\n");
    . fb_name: The name of the framebuffer
    . x:       The logo horizontal position.
    . y:       The logo vertical position.
    . w:       The logo width.
    . h:       The logo height.

The added built-in logo is the one of the IRT SystemX.

Signed-off-by: Jimmy Durand Wesolowski <jimmy.durand-wesolowski@openwide.fr>
[COMMANDS] Adding the "fb image" command, to display an image on a framebuffer.

This "fb image" command takes the following argument:
- the framebuffer to display the image on
- the image path
- the "x", the horizontal offset on the screen
- the "y", the vertical offset on the screen

Signed-off-by: Jimmy Durand Wesolowski <jimmy.durand-wesolowski@openwide.fr>
[CORE] Add config option for VA Pool aligment size

Buddy initialization for VA pool has the requirement
of aligning with the max bin selected for buddy.
As part of commit 82553c1a99dc75363b1c437eff8ece419dcef607
the max bins were increased to 23 for support 8MB. This
imposes VA pool alignment of 8MB.

x86 uses alignmen of 2MB and uses it as text start.

This patch makes this configuration a architecture specific
config option.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>