spi: spi-geni-qcom: Set the clock properly at runtime resume

In the patch ("spi: spi-geni-qcom: Avoid clock setting if not needed")
we avoid a whole pile of clock code.  As part of that, we should have
restored the clock at runtime resume.  Do that.

It turns out that, at least with today's configurations, this doesn't
actually matter.  That's because none of the current device trees have
an OPP table for geni SPI yet.  That makes dev_pm_opp_set_rate(dev, 0)
a no-op.  This is why it wasn't noticed in the testing of the original
patch.  It's still a good idea to fix, though.
Reviewed-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200709074037.v2.1.I0b701fc23eca911a5bde4ae4fa7f97543d7f960e@changeidSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/spi/spi-geni-qcom.c

@@ -78,6 +78,7 @@ struct spi_geni_master {
 	u32 fifo_width_bits;
 	u32 tx_wm;
 	unsigned long cur_speed_hz;
+	unsigned long cur_sclk_hz;
 	unsigned int cur_bits_per_word;
 	unsigned int tx_rem_bytes;
 	unsigned int rx_rem_bytes;
@@ -115,6 +116,9 @@ static int get_spi_clk_cfg(unsigned int speed_hz,
 	ret = dev_pm_opp_set_rate(mas->dev, sclk_freq);
 	if (ret)
 		dev_err(mas->dev, "dev_pm_opp_set_rate failed %d\n", ret);
+	else
+		mas->cur_sclk_hz = sclk_freq;
+
 	return ret;
 }
 
@@ -674,7 +678,11 @@ static int __maybe_unused spi_geni_runtime_resume(struct device *dev)
 	if (ret)
 		return ret;
 
-	return geni_se_resources_on(&mas->se);
+	ret = geni_se_resources_on(&mas->se);
+	if (ret)
+		return ret;
+
+	return dev_pm_opp_set_rate(mas->dev, mas->cur_sclk_hz);
 }
 
 static int __maybe_unused spi_geni_suspend(struct device *dev)