ARM: versatilepb : drop warnings due to double definitions

CONFIG_ARCH_VERSATILE_PB  is defined twice - drop
the define from config.h.

Signed-off-by: Stefano Babic <sbabic@denx.de>
diff --git a/boards.cfg b/boards.cfg
index abee821..413ab92 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -77,7 +77,7 @@
 omap1510inn                  arm         arm925t     -                   ti
 integratorap_cm926ejs        arm         arm926ejs   integrator          armltd         -           integratorap
 integratorcp_cm926ejs        arm         arm926ejs   integrator          armltd         -           integratorcp
-versatileqemu                arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_QEMU
+versatileqemu                arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_QEMU,ARCH_VERSATILE_PB
 versatilepb                  arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_PB
 versatileab                  arm         arm926ejs   versatile           armltd         versatile   versatile:ARCH_VERSATILE_AB
 aspenite                     arm         arm926ejs   -                   Marvell        armada100