powerpc: cpm2 boards: update fcc register logic

In the recent dropping of !NET_MULTI code (commit e2a53458a7ab37523304),
I misread the logic in include/net.h.  Some of it was used by NET_MULTI
code as glue between the multi/non-multi worlds for cpm2 boards.

Rather than restore the block of code, push the logic to the board config
headers where it all belongs.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/configs/stxgp3.h b/include/configs/stxgp3.h
index 90d249b..6f611be 100644
--- a/include/configs/stxgp3.h
+++ b/include/configs/stxgp3.h
@@ -255,8 +255,8 @@
    * - Select bus for bd/buffers
    * - Full duplex
    */
-  #define CONFIG_SYS_CMXFCR_MASK       (CMXFCR_FC2 | CMXFCR_RF2CS_MSK | CMXFCR_TF2CS_MSK)
-  #define CONFIG_SYS_CMXFCR_VALUE      (CMXFCR_RF2CS_CLK13 | CMXFCR_TF2CS_CLK14)
+  #define CONFIG_SYS_CMXFCR_MASK2      (CMXFCR_FC2 | CMXFCR_RF2CS_MSK | CMXFCR_TF2CS_MSK)
+  #define CONFIG_SYS_CMXFCR_VALUE2     (CMXFCR_RF2CS_CLK13 | CMXFCR_TF2CS_CLK14)
   #define CONFIG_SYS_CPMFCR_RAMTYPE    0
 #if 0
   #define CONFIG_SYS_FCC_PSMR          (FCC_PSMR_FDE)