ARM: defconfig: Disable PREEMPT again on multi_v7

I should have let this soak for a while in linux-next, since we have at
least one board that hit a regression from it. Revert from 4.20-rc, and
we'll queue it for next merge window once regression is fixed.

This reverts commit 513eb985.
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/configs/multi_v7_defconfig

 CONFIG_SYSVIPC=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y
-CONFIG_PREEMPT=y
 CONFIG_CGROUPS=y
 CONFIG_BLK_DEV_INITRD=y
 CONFIG_EMBEDDED=y