This resolves a hazard between a mtc0 and a mfc0 instruction after
activating the DSP support. Without this fix the CPU could use the old
value again and the DSP support would not be active.
Fixes: FS#2928, FS#2899
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de> [ath79/tl-wdr3600; ath79/tl-wdr4300]
Tested-by: David Bauer <mail@david-bauer.net> [ocedo_koala/ocedo_raccoon]
