drm/rockchip: fix typo in Kconfig 's/HDMI/dsi/'

In the help of ROCKCHIP_DW_MIPI_DSI it said
it is a HDMI driver instead of a dsi driver.

Signed-off-by: Dafna Hirschfeld <[e-mail]>
Signed-off-by: Heiko Stuebner <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/rockchip/Kconfig

···
 	select GENERIC_PHY_MIPI_DPHY
 	help
 	  This selects support for Rockchip SoC specific extensions
-	  for the Synopsys DesignWare HDMI driver. If you want to
+	  for the Synopsys DesignWare dsi driver. If you want to
 	  enable MIPI DSI on RK3288 or RK3399 based SoC, you should
 	  select this option.