brcmfmac: Replace zero-length array with flexible array member

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use "flexible array members"[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

Also, make use of the struct_size() helper in devm_kzalloc().

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#zero-length-and-one-element-arraysSigned-off-by: Len Baker <len.baker@gmx.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210904092217.2848-1-len.baker@gmx.com

drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c

@@ -29,7 +29,7 @@ static int brcmf_of_get_country_codes(struct device *dev,
 		return (count == -EINVAL) ? 0 : count;
 	}
 
-	cc = devm_kzalloc(dev, sizeof(*cc) + count * sizeof(*cce), GFP_KERNEL);
+	cc = devm_kzalloc(dev, struct_size(cc, table, count), GFP_KERNEL);
 	if (!cc)
 		return -ENOMEM;
 

include/linux/platform_data/brcmfmac.h

@@ -125,7 +125,7 @@ struct brcmfmac_pd_cc_entry {
  */
 struct brcmfmac_pd_cc {
 	int				table_size;
-	struct brcmfmac_pd_cc_entry	table[0];
+	struct brcmfmac_pd_cc_entry	table[];
 };
 
 /**