can: rcar_canfd: Fix R-Car V3U GAFLCFG field accesses

Each Global Acceptance Filter List Configuration Register (GAFLCFG)
contains two fields, and stores the number of channel rules for one
channel pair.

As R-Car V3U and later can have more than 2 channels, the field
selection should be based on the LSB (even or odd) of the channel
number, instead of on the full channel number.

Fixes: 45721c40 ("can: rcar_canfd: Add support for r8a779a0 SoC")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/all/36bcf0ffb96d6aaed970751f9546b901af638bcf.1674499048.git.geert+renesas@glider.beSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/rcar/rcar_canfd.c

@@ -92,10 +92,10 @@
 /* RSCFDnCFDGAFLCFG0 / RSCFDnGAFLCFG0 */
 #define RCANFD_GAFLCFG_SETRNC(gpriv, n, x) \
 	(((x) & reg_v3u(gpriv, 0x1ff, 0xff)) << \
-	 (reg_v3u(gpriv, 16, 24) - (n) * reg_v3u(gpriv, 16, 8)))
+	 (reg_v3u(gpriv, 16, 24) - ((n) & 1) * reg_v3u(gpriv, 16, 8)))
 
 #define RCANFD_GAFLCFG_GETRNC(gpriv, n, x) \
-	(((x) >> (reg_v3u(gpriv, 16, 24) - (n) * reg_v3u(gpriv, 16, 8))) & \
+	(((x) >> (reg_v3u(gpriv, 16, 24) - ((n) & 1) * reg_v3u(gpriv, 16, 8))) & \
 	 reg_v3u(gpriv, 0x1ff, 0xff))
 
 /* RSCFDnCFDGAFLECTR / RSCFDnGAFLECTR */