mmc: sdhci-omap: don't misuse kernel-doc marker

Use "/*" instead of "/**" for common C comments to prevent warnings
from scripts/kernel-doc.

sdhci-omap.c:3: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
sdhci-omap.c:3: warning: missing initial short description on line:
 * SDHCI Controller driver for TI's OMAP SoCs

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202311201117.lFxgJTK6-lkp@intel.com/
Link: https://lore.kernel.org/r/20231206055855.21092-1-rdunlap@infradead.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>