intel_th: msu: Fix kernel-doc warnings

Correct function comments to prevent kernel-doc warnings
found when using "W=1".

msu.c:77: warning: Function parameter or member 'msc' not described in 'msc_window'
msu.c:122: warning: bad line:
msu.c:760: warning: No description found for return value of 'msc_configure'
msu.c:1309: warning: Function parameter or member 'nr_pages' not described in 'msc_buffer_alloc'
msu.c:1309: warning: Function parameter or member 'nr_wins' not described in 'msc_buffer_alloc'
msu.c:1309: warning: Excess function parameter 'size' description in 'msc_buffer_alloc'
msu.c:1376: warning: No description found for return value of 'msc_buffer_free_unless_used'
msu.c:1444: warning: No description found for return value of 'msc_win_to_user'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240429130119.1518073-10-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>