powerpc: remove RPXClassic, RPXlite boards support

Enough time has passed since these boards were moved to Orphan. Remove.

 - Remove board/RPXlite/*
 - Remove board/RPXClassic/*
 - Remove include/configs/RPXlite.h
 - Remove include/configs/RPXClassic.h
 - Clean-up defined(CONFIG_RPXCLASSIC)
 - Move the entry from boards.cfg to doc/README.scrapyard

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/powerpc/cpu/mpc8xx/serial.c b/arch/powerpc/cpu/mpc8xx/serial.c
index f7ca11e..9321411 100644
--- a/arch/powerpc/cpu/mpc8xx/serial.c
+++ b/arch/powerpc/cpu/mpc8xx/serial.c
@@ -182,7 +182,7 @@
 #endif
 #endif	/* CONFIG_FADS */
 
-#if defined(CONFIG_RPXLITE) || defined(CONFIG_RPXCLASSIC)
+#if defined(CONFIG_RPXLITE)
 	/* Enable Monitor Port Transceiver */
 	*((uchar *) BCSR0) |= BCSR0_ENMONXCVR ;
 #endif /* CONFIG_RPXLITE */