clk-bcm2835: Avoid null pointer exception

raspberrypi inclusion
category: feature
bugzilla: 50432

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clk_desc_array[BCM2835_PLLB] doesn't exist so we dereference null when iterating
Signed-off-by: Npopcornmix <popcornmix@gmail.com>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/clk/bcm/clk-bcm2835.c

@@ -2310,9 +2310,11 @@ static bool bcm2835_clk_is_claimed(const char *name)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(clk_desc_array); i++) {
-		const char *clk_name = *(const char **)(clk_desc_array[i].data);
-		if (!strcmp(name, clk_name))
-		    return bcm2835_clk_claimed[i];
+		if (clk_desc_array[i].data) {
+			const char *clk_name = *(const char **)(clk_desc_array[i].data);
+			if (!strcmp(name, clk_name))
+				return bcm2835_clk_claimed[i];
+		}
 	}
 
 	return false;