Update FAQ.md

Latest version of boot2docker appears to run with 2048 megabytes of memory.

$ boot2docker info
{
	"Name": "boot2docker-vm",
	"UUID": "c58b1294-e2c6-4dc0-b825-5657eb5eca26",
	"Iso": "/Users/robin/.boot2docker/boot2docker.iso",
	"State": "running",
	"CPUs": 8,
	"Memory": 2048,
	"VRAM": 8,
	"CfgFile": "/Users/robin/VirtualBox VMs/boot2docker-vm/boot2docker-vm.vbox",
	"BaseFolder": "/Users/robin/VirtualBox VMs/boot2docker-vm",
	"OSType": "",
	"Flag": 0,
	"BootOrder": null,
	"DockerPort": 0,
	"SSHPort": 2022,
	"SerialFile": "/Users/robin/.boot2docker/boot2docker-vm.sock"
}