armvirt: re-enable VFP support

Enable CONFIG_VFP again which was disabled during the 4.9 -> 4.14 bump.

Boot tested both 32 and 64 bit subtargets using initramfs images with the
qemu-system-arm and qemu-system-aarch64 emulators.

Fixes: aa100b66f2 ("armvirt: bump to v4.14")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/armvirt/config-4.14

@@ -238,7 +238,6 @@ CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
 CONFIG_USB_SUPPORT=y
 CONFIG_USE_OF=y
 CONFIG_VECTORS_BASE=0xffff0000
-# CONFIG_VFP is not set
 CONFIG_VIRTIO=y
 CONFIG_VIRTIO_BALLOON=y
 CONFIG_VIRTIO_BLK=y