uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/os-specific/linux/kernel/genksyms-fix-segfault.patch

@@ -0,0 +1,19 @@
+diff --git a/scripts/genksyms/genksyms.c b/scripts/genksyms/genksyms.c
+index 88632df..ba6cfa9 100644
+--- a/scripts/genksyms/genksyms.c
++++ b/scripts/genksyms/genksyms.c
+@@ -233,11 +233,11 @@ static struct symbol *__add_symbol(const char *name, enum symbol_type type,
+ 		free_list(last_enum_expr, NULL);
+ 		last_enum_expr = NULL;
+ 		enum_counter = 0;
+-		if (!name)
+-			/* Anonymous enum definition, nothing more to do */
+-			return NULL;
+ 	}
+ 
++	if (!name)
++		return NULL;
++
+ 	h = crc32(name) % HASH_BUCKETS;
+ 	for (sym = symtab[h]; sym; sym = sym->hash_next) {
+ 		if (map_to_ns(sym->type) == map_to_ns(type) &&