mor1kx_ctrl_cappuccino: fix spr_access_ack[`OR1K_SPR_SYS_BASE] and clean up DEBUGUNIT
mor1kx_pic, mor1kx_ticktimer: use spr_access_i on all spr_addr check
cappuccino/ctrl: left justify generate statements
cappuccino/ctrl: negate external spr units on non access

This ensures that the external spr units can't assert their
acks when they are not accessed (this logic has changed,
earlier they've been allowed to constantly assert ack).

This together with the data negation should be moved to respective
spr units at some point.