fbdev: update s1d13xxxfb to differ between revisions and production ids

The s1d13xxx chip provides two values of identification value: the
Production id (e.g 13506/13505/13806..) and a revision number 0,1,2,3).
Together these can help us to differentiate between similiar setups.

This patch adds the proper way of grabbing both those values and save them
for future reference (in order to decide what functions a card supports,
e.g acceleration).

We also move away from the concept of all s1d13xxx = s1d13806 when we
really support alot more.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: simplify s1d13xxxfb_probe()]
Signed-off-by: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>