configs: compile cirrus driver as modules for qboot optimization

To compile as modules can make the driver init parallel with systemd
startup, which can save about 40ms startup time.
Signed-off-by: NShile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

config-4.19.y-x86_64

@@ -2623,7 +2623,7 @@ CONFIG_DRM_I915_GVT=y
 # CONFIG_DRM_UDL is not set
 CONFIG_DRM_AST=m
 # CONFIG_DRM_MGAG200 is not set
-CONFIG_DRM_CIRRUS_QEMU=y
+CONFIG_DRM_CIRRUS_QEMU=m
 CONFIG_DRM_QXL=y
 CONFIG_DRM_BOCHS=y
 # CONFIG_DRM_VIRTIO_GPU is not set

config-4.19.y-x86_64-debug

@@ -2626,7 +2626,7 @@ CONFIG_DRM_I915_GVT=y
 # CONFIG_DRM_UDL is not set
 CONFIG_DRM_AST=m
 # CONFIG_DRM_MGAG200 is not set
-CONFIG_DRM_CIRRUS_QEMU=y
+CONFIG_DRM_CIRRUS_QEMU=m
 CONFIG_DRM_QXL=y
 CONFIG_DRM_BOCHS=y
 # CONFIG_DRM_VIRTIO_GPU is not set