cmd: qfw: do not depend on x86

The qfw command interface used to depend on X86, this patch removes
this restriction so it can be built for sandbox for testing. For normal
usage, it can only be used with CONFIG_QEMU.

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

cmd/Kconfig

@@ -595,7 +595,6 @@ config CMD_SOUND
 
 config CMD_QFW
 	bool "qfw"
-	depends on X86
 	select QFW
 	help
 	  This provides access to the QEMU firmware interface.  The main