of: reserved_mem: Fix typo in the too-many-regions message

Minor fix for a missing preposition in the error message that appears
when there are too many reserved memory regions for the allocated array
to store.

Signed-off-by: Danny Lin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

drivers/of/of_reserved_mem.c

···
 	struct reserved_mem *rmem = &reserved_mem[reserved_mem_count];
 
 	if (reserved_mem_count == ARRAY_SIZE(reserved_mem)) {
-		pr_err("not enough space all defined regions.\n");
+		pr_err("not enough space for all defined regions.\n");
 		return;
 	}