If spectral scan support is enabled then ath10k-ct will cause a NULL
pointer due to relay_open() being called with a const callback struct
which is only supported in kernel 5.11 and later.
So, simply check the kernel version and if 5.11 and newer use the const
callback struct, otherwise use the regular struct.
Fixes: 553a3ac ("ath10k-ct: use 5.15 version")
Signed-off-by: Robert Marko <robimarko@gmail.com>
