Prevented IRQ related CSR update to be overwritten by duplicate regul…
Created by: Silabs-ArjanB
Prevented IRQ related CSR update to be overwritten by duplicate regular CSR write. CSR writes are now only performed during the initial cycle in EX.
Fix for CSR + IRQ conflict from #460 (closed)
Signed-off-by: Arjan Bink Arjan.Bink@silabs.com