accel/ivpu: Compile ivpu_debugfs.c conditionally

Only compile ivpu_debugfs.c file with CONFIG_DEBUG_FS.

Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230907072610.433497-2-stanislaw.gruszka@linux.intel.com