scsi: ufs: ufs-exynos: Demote seemingly unintentional kerneldoc header

This is the only use of kerneldoc in the source file and no descriptions
are provided.

Fixes the following W=1 kernel build warning(s):

In file included from drivers/scsi/ufs/ufs-exynos.c:23:
drivers/scsi/ufs/ufs-exynos.c:234: warning: Function parameter or member 'ufs' not described in 'exynos_ufs_auto_ctrl_hcc'
drivers/scsi/ufs/ufs-exynos.c:234: warning: Function parameter or member 'en' not described in 'exynos_ufs_auto_ctrl_hcc'

Link: https://lore.kernel.org/r/[e-mail]
Cc: Alim Akhtar <[e-mail]>
Cc: Avri Altman <[e-mail]>
Cc: Kukjin Kim <[e-mail]>
Cc: Krzysztof Kozlowski <[e-mail]>
Cc: Seungwon Jeon <[e-mail]>
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/ufs/ufs-exynos.c

···
 	return 0;
 }
 
-/**
+/*
  * exynos_ufs_auto_ctrl_hcc - HCI core clock control by h/w
  * Control should be disabled in the below cases
  * - Before host controller S/W reset