This fixes the following warnings while building in W=1 :
dw-mipi-dsi.c:1002:5: warning: no previous prototype for 'dw_mipi_dsi_debugfs_write' [-Wmissing-prototypes]
dw-mipi-dsi.c:1027:5: warning: no previous prototype for 'dw_mipi_dsi_debugfs_show' [-Wmissing-prototypes]
Fixes: e2435d69204c ("drm/bridge: dw-mipi-dsi.c: Add VPG runtime config through debugfs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Angelo Ribeiro <angelo.ribeiro@synopsys.com>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200907102711.23748-1-narmstrong@baylibre.com
 
 
 #ifdef CONFIG_DEBUG_FS
 
-int dw_mipi_dsi_debugfs_write(void *data, u64 val)
+static int dw_mipi_dsi_debugfs_write(void *data, u64 val)
 {
        struct debugfs_entries *vpg = data;
        struct dw_mipi_dsi *dsi;
        return 0;
 }
 
-int dw_mipi_dsi_debugfs_show(void *data, u64 *val)
+static int dw_mipi_dsi_debugfs_show(void *data, u64 *val)
 {
        struct debugfs_entries *vpg = data;