net: mvpp2: Fix clk error path in mvpp2_probe

When clk_prepare_enable fails for the axi_clk, the mg_clk isn't properly
cleaned up. Add another jump label to handle that case, and make sure we
jump to it in the later error cases.

Fixes: 4792ea04 ("net: mvpp2: Fix clock resource by adding an optional bus clock")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>