Final tiny changes to ADC!

Removed illegal values check inside init function and removed test for that.
Added the rest of the registers to the struct for consistency reasons and
found out that neither ADC nor DACC work anymore. Seems to be the PMC.

pmc_enable_peripheral_clock(ID_ADC);
pmc_peripheral_clock_enabled(ID_ADC);

will generate FALSE.
Why is this? Need fix before merge!
Merge branch 'refactor_API' of https://github.com/theolind/mahm3lib into refactor_API