soc: fsl: guts: fix comment syntax in file

The opening comment mark '/**' is used for kernel-doc comments.
There are certain comments in include/linux/fsl/guts.h which follows this
syntax, but the content inside does not comply with kernel-doc.

E.g., opening comment for "Freecale 85xx and 86xx Global Utilties
register set" follows kernel-doc syntax(i.e., '/**'), but the content
inside does not comply with any kernel-doc specification (function,
struct, etc).

This causes unwelcomed warning from kernel-doc:
"warning: expecting prototype for Freecale 85xx and 86xx Global Utilties register set(). Prototype was for __FSL_GUTS_H__() instead"

Replace all such comment occurrences with general comment format,
i.e. '/*' to pervent kernel-doc from parsing these.

Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Li Yang <leoyang.li@nxp.com>