clk: qcom: Use parent rate when set rate to pixel RCG clock

commit 6d451367 upstream.

Since the parent rate has been recalculated, pixel RCG clock
should rely on it to find the correct M/N values during set_rate,
instead of calling __clk_round_rate() to its parent again.
Signed-off-by: Hai Li <hali@codeaurora.org>
Tested-by: Archit Taneja <architt@codeaurora.org>
Fixes: 99cbd064 ("clk: qcom: Support display RCG clocks")
[sboyd@codeaurora.org: Silenced unused parent variable warning]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[ kamal: backport to 3.19-stable: context ]
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/clk/qcom/clk-rcg2.c

@@ -508,18 +508,16 @@ static int clk_pixel_set_rate(struct clk_hw *hw, unsigned long rate,
 	struct clk_rcg2 *rcg = to_clk_rcg2(hw);
 	struct freq_tbl f = *rcg->freq_tbl;
 	const struct frac_entry *frac = frac_table_pixel;
-	unsigned long request, src_rate;
+	unsigned long request;
 	int delta = 100000;
 	u32 mask = BIT(rcg->hid_width) - 1;
 	u32 hid_div;
-	struct clk *parent = clk_get_parent_by_index(hw->clk, f.src);
 
 	for (; frac->num; frac++) {
 		request = (rate * frac->den) / frac->num;
 
-		src_rate = __clk_round_rate(parent, request);
-		if ((src_rate < (request - delta)) ||
-			(src_rate > (request + delta)))
+		if ((parent_rate < (request - delta)) ||
+			(parent_rate > (request + delta)))
 			continue;
 
 		regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG,