x86: qemu: split qfw command interface and qfw core

This patch splits qfw command interface and qfw core function into two
files, and introduces a new Kconfig option (CONFIG_QFW) for qfw core.

Now when qfw command interface is enabled, it will automatically select
qfw core. This patch also makes the ACPI table generation select
CONFIG_QFW.

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/cmd/Makefile b/cmd/Makefile
index d4432c8..ff4fc5b 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -105,7 +105,7 @@
 obj-y += pcmcia.o
 obj-$(CONFIG_CMD_PORTIO) += portio.o
 obj-$(CONFIG_CMD_PXE) += pxe.o
-obj-$(CONFIG_CMD_QEMU_FW_CFG) += qemu_fw_cfg.o
+obj-$(CONFIG_CMD_QEMU_FW_CFG) += qfw.o
 obj-$(CONFIG_CMD_READ) += read.o
 obj-$(CONFIG_CMD_REGINFO) += reginfo.o
 obj-$(CONFIG_CMD_REISER) += reiser.o