omap: rx51_defconfig: Remove duplicate phonet

Phonet is enabled by the commit bce54fed
and this duplicate gives a warning when doing make rx51_defconfig.
Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/configs/rx51_defconfig

@@ -480,7 +480,6 @@ CONFIG_BT_HIDP=m
 # CONFIG_BT_HCIBFUSB is not set
 # CONFIG_BT_HCIVHCI is not set
 # CONFIG_AF_RXRPC is not set
-# CONFIG_PHONET is not set
 CONFIG_WIRELESS=y
 CONFIG_CFG80211=y
 # CONFIG_CFG80211_REG_DEBUG is not set