x86/kgdb: Fix a kerneldoc warning when build with W=1

When compiled with W=1, the following warning is generated:

  arch/x86/kernel/kgdb.c:698: warning: Cannot understand  *
   on line 698 - I thought it was a doc line

Remove the corresponding empty comment line to fix the warning.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/aad659537c1d4ebd86912a6f0be458676c8e69af.1695401178.git.christophe.jaillet@wanadoo.fr