[PATCH] ptp: ptp_clockmatrix: repair non-kernel-doc comment

Do not use "/**" to begin a comment that is not in kernel-doc format.

Prevents this docs build warning:

drivers/ptp/ptp_clockmatrix.c:1679: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
    * Maximum absolute value for write phase offset in picoseconds

Fixes: 794c3dffacc16 ("ptp: ptp_clockmatrix: Add support for FW 5.2 (8A34005)")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <redacted>
Cc: Min Li <redacted>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
---
 drivers/ptp/ptp_clockmatrix.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20211110.orig/drivers/ptp/ptp_clockmatrix.c
+++ linux-next-20211110/drivers/ptp/ptp_clockmatrix.c

@@ -1699,7 +1699,7 @@ static int initialize_dco_operating_mode
 
 /* PTP Hardware Clock interface */
 
-/**
+/*
  * Maximum absolute value for write phase offset in picoseconds
  *
  * @channel:  channel