sprs: add immu and dmmy configuration register definitions
cfgrs: add dmmucfgr and immucfgr registers
cappuccino/fetch: code cleanup
cappuccino/lsu: hold ctrl_lsu_adr_i when no lsu op is in exec
cappuccino/execute_ctrl: prevent multicycle mfspr wb

This patch prevents the write enable signal from being
asserted for more than one cycle when ctrl/mem stage is stalled.
cappuccino/rf: Fix typo
cappuccino/ctrl: default spr acks to 1 instead of 0

If the ack is to be used for mfspr this is necessary
for reading out 0 as default, otherwise the cpu will lock-up
while waiting for the ack.