Update 9tcfg.c

Shadowrom and maprom commands will no longer interrupt startup-sequence when tried to applied again if already active, using other options together with "shadowrom on" and "maprom on" is now possible, adding another line in s-s to add more mem ("9tcfg moremem") is no longer necessary.
e.g.:
9tcfg maprom on loadrom=ksx.x moremem reboot >NIL:    - moremem will work at every boot