nouveau: import nvif/ioctl.h file from libdrm_nouveau
Technically this is UAPI and should be moved into the UAPI headers, but for now let's unbreak users this way.
Fixes: 821f4c8d ("nouveau: import libdrm_nouveau")
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Technically this is UAPI and should be moved into the UAPI headers, but for now let's unbreak users this way.
Fixes: 821f4c8d ("nouveau: import libdrm_nouveau")