drm/exynos/exynos_drm_ipp: Fix documentation for 'exynos_drm_ipp_get_{caps,res}_ioctl()'

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

 drivers/gpu/drm/exynos/exynos_drm_ipp.c:105: warning: expecting prototype for exynos_drm_ipp_ioctl_get_res_ioctl(). Prototype was for exynos_drm_ipp_get_res_ioctl() instead
 drivers/gpu/drm/exynos/exynos_drm_ipp.c:153: warning: expecting prototype for exynos_drm_ipp_ioctl_get_caps(). Prototype was for exynos_drm_ipp_get_caps_ioctl() instead

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602143300.2330146-25-lee.jones@linaro.org