Correct typos in thead_c9xx.h

[felixonmars]

[avpatel]

We have mailing list based patch review so it would be great if you can send these patchs to OpenSBI mailing list.

You need to join OpenSBI mailing list using following link http://lists.infradead.org/mailman/listinfo/opensbi

Make sure you use "git send-email" to send the patches.

Regards, Anup

[avpatel]

The file thead_c9xx.h does not exists anymore.