sos_kernel:fix the failure of opening /dev/btrfs-control devcie file

to run LTP test tool on sos.

The ioctl08 file excute fail on SOS kernel,because SOS is short of
"/dev/btrfs-control" device file.Root cause is that btrfs filesystem
configuration option was disable.Add "CONFIG_BTRFS_FS=y" into
kernel_config_uefi_sos and rebuild SOS kernel,the function is normal.

Tracked-On:projectacrn/acrn-hypervisor#3503
Signed-off-by: liuyonggang <yonggangx.liu@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>

kernel_config_uefi_sos

@@ -5630,7 +5630,7 @@ CONFIG_FS_MBCACHE=y
 # CONFIG_XFS_FS is not set
 # CONFIG_GFS2_FS is not set
 # CONFIG_OCFS2_FS is not set
-# CONFIG_BTRFS_FS is not set
+CONFIG_BTRFS_FS=y
 # CONFIG_NILFS2_FS is not set
 # CONFIG_F2FS_FS is not set
 # CONFIG_FS_DAX is not set