gcov: fix kernel-doc markup issue

gcov: fix kernel-doc markup issue

Fix the following kernel-doc issue in gcov:

  kernel/gcov/gcc_4_7.c:238: warning: Function parameter or member 'dst' not described in 'gcov_info_add'
  kernel/gcov/gcc_4_7.c:238: warning: Function parameter or member 'src' not described in 'gcov_info_add'
  kernel/gcov/gcc_4_7.c:238: warning: Excess function parameter 'dest' description in 'gcov_info_add'
  kernel/gcov/gcc_4_7.c:238: warning: Excess function parameter 'source' description in 'gcov_info_add'

Link: https://lkml.kernel.org/r/1605252352-63983-1-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>