fbdev: c2p/atafb - Add support for Atari interleaved bitplanes

The c2p() for normal bitplanes is not suitable for interleaved bitplanes with
2 bytes of interleave, causing a garbled penguin logo. Add c2p_iplan2().

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index e39e33e..4fc29ea 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -72,7 +72,7 @@
 obj-$(CONFIG_FB_LEO)              += leo.o sbuslib.o
 obj-$(CONFIG_FB_SGIVW)            += sgivwfb.o
 obj-$(CONFIG_FB_ACORN)            += acornfb.o
-obj-$(CONFIG_FB_ATARI)            += atafb.o c2p.o atafb_mfb.o \
+obj-$(CONFIG_FB_ATARI)            += atafb.o c2p_iplan2.o atafb_mfb.o \
                                      atafb_iplan2p2.o atafb_iplan2p4.o atafb_iplan2p8.o
 obj-$(CONFIG_FB_MAC)              += macfb.o
 obj-$(CONFIG_FB_HECUBA)           += hecubafb.o