Fix kernel-doc warnings reported by the kernel test robot:

drivers/platform/mellanox/mlxbf-pmc.c:82: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Structure to hold attribute and block info for each sysfs entry
drivers/platform/mellanox/mlxbf-pmc.c:94: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Structure to hold info for each HW block
drivers/platform/mellanox/mlxbf-pmc.c:121: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Structure to hold PMC context info
drivers/platform/mellanox/mlxbf-pmc.c:148: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Structure to hold supported events for each block

Also fix typos in a few struct member names.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Aditya Srivastava <yashsri421@gmail.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Mark Gross <mgross@linux.intel.com>
Cc: Vadim Pasternak <vadimp@nvidia.com>
Cc: platform-driver-x86@vger.kernel.org
Link: https://lore.kernel.org/r/20210822171742.26921-1-rdunlap@infradead.orgSigned-off-by: Hans de Goede <hdegoede@redhat.com>