wifi: ath10k: use flexible arrays for WMI start scan TLVs

Currently ath10k defines the following struct:
	struct wmi_start_scan_tlvs {
		u8 tlvs[0];
	} __packed;

Per the guidance in [1] this should be a flexible array. However, a
direct replace to u8 tlvs[] results in the compilation error:
       flexible array member in a struct with no named members

This is because C99 6.7.2.1 (16) requires that a structure containing
a flexible array member must have more than one named member.

So rather than defining a separate struct wmi_start_scan_tlvs which
contains the flexible tlvs[] array, just define the tlvs[] array where
struct wmi_start_scan_tlvs is being used.

No functional changes, compile tested only.

[1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays



Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20231213-wmi_host_mem_chunks_flexarray-v1-2-92922d92fa2c@quicinc.com