powerpc: mpc85xx: Implemente workaround for CPU erratum A-007907

Core hang occurs when using L1 stashes. Workaround is to disable L1
stashes so software uses L2 cache for stashes instead.

Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Darwin Dingel <darwin.dingel@alliedtelesis.co.nz>
Cc: York Sun <york.sun@nxp.com>
[York S: Move SYS_FSL_ERRATUM_A007907 to Kconfig]
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc85xx/cmd_errata.c b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
index 54b5b33..822ae72 100644
--- a/arch/powerpc/cpu/mpc85xx/cmd_errata.c
+++ b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
@@ -330,7 +330,9 @@
 #ifdef CONFIG_SYS_FSL_ERRATUM_A009663
 	puts("Work-around for Erratum A009663 enabled\n");
 #endif
-
+#ifdef CONFIG_SYS_FSL_ERRATUM_A007907
+	puts("Work-around for Erratum A007907 enabled\n");
+#endif
 	return 0;
 }