ipq40xx: 5.15: add patch commenting unused sdhci function

ipq40xx: 5.15: add patch commenting unused sdhci function

Add patch commenting unused sdhci function, hopin this will be dropped
when the problem is actually found.
Fix compilation warning:
drivers/mmc/host/sdhci-msm.c:1781:13: error: 'sdhci_msm_set_clock' defined but not used [-Werror=unused-function]
 1781 | static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock)
      |             ^~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>