clk: rockchip: add sclk_mac_lbtest to rk3188_critical_clocks

Since the loopbacktest clock is not exported and is not touched in the
driver, it has to be added to rk3188_critical_clocks to be protected from
being disabled and in order to get the emac working.
Signed-off-by: Alex Bee <knaerzche@gmail.com>
Link: https://lore.kernel.org/r/20200722161820.5316-1-knaerzche@gmail.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

drivers/clk/rockchip/clk-rk3188.c

@@ -751,6 +751,7 @@ static const char *const rk3188_critical_clocks[] __initconst = {
 	"pclk_peri",
 	"hclk_cpubus",
 	"hclk_vio_bus",
+	"sclk_mac_lbtest",
 };
 
 static struct rockchip_clk_provider *__init rk3188_common_clk_init(struct device_node *np)