ASoC: Intel: Skylake: Avoid the use of one-element array

One-element arrays are being deprecated[1]. Replace the one-element
array with a simple value type 'u8 reserved'[2], once it seems this
is just a placeholder for alignment.

[1] KSPP/linux#79
[2] KSPP/linux#86

Signed-off-by: Gustavo A. R. Silva <[email protected]>
Tested-by: kernel test robot <[email protected]>
Reviewed-by: Amadeusz Sławiński <[email protected]>
Link: https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/0-day/skylake-20200717.md
Link: https://lore.kernel.org/r/20200717215500.GA13910@embeddedor
Signed-off-by: Mark Brown <[email protected]>

sound/soc/intel/skylake/skl-topology.h

@@ -97,7 +97,7 @@ struct skl_audio_data_format {
 	u8 number_of_channels;
 	u8 valid_bit_depth;
 	u8 sample_type;
-	u8 reserved[1];
+	u8 reserved;
 } __packed;
 
 struct skl_base_cfg {