Fix some incorrect colour-to-resistance results. The price is that sometimes the display is subobtimal (like "2000 Ohms" instead of "2 KOhms")
Ideally, unit prefixes (K, M,...) should be calculated separately, but the largest resistance we can handle is 99 MOhm, which wouldn't fit in a 32 bit int (using our centiohm internal units) if we didn't cheat. (and technically we could go higher still. white-white-white would be 99 GOhm, but we don't do such high multipliers now)
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28272 a1c6a512-1295-4272-9138-f99709370657