util: store number of colors for indexed formats

util: store number of colors for indexed formats

Store the number of available colors for color-indexed frame
buffer formats in the format_info[] array.  This avoids the need of test
code for having to use switch statements all the time to obtain the
number of colors, or to check if a mode is color-indexed or not.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
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v5:
  - Add Reviewed-by,

v4:
  - No changes,

v3:
  - Add Acked-by,

v2:
  - New.