clk: tegra: fix error return case for recalc_rate

tegra-bpmp clocks driver makes implicit conversion of signed error
code to unsigned value in recalc_rate operation. The behavior for
recalc_rate, according to it's specification, should be that "If the
driver cannot figure out a rate for this clock, it must return 0."

Fixes: ca6f2796ee ("clk: tegra: Add BPMP clock driver")
Signed-off-by: Timo Alho <talho@nvidia.com>
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Link: https://lore.kernel.org/r/20230912112951.2330497-1-cyndis@kapsi.fi
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/tegra/clk-bpmp.c

@@ -159,7 +159,7 @@ static unsigned long tegra_bpmp_clk_recalc_rate(struct clk_hw *hw,
 
 	err = tegra_bpmp_clk_transfer(clk->bpmp, &msg);
 	if (err < 0)
-		return err;
+		return 0;
 
 	return response.rate;
 }