[PATCH v3] Documentation:openrisc: Add build instructions with initramfs

[Ann Yun <by.ann.yun@gmail.com>]

Mention how to include initramfs when building the kernel and
direct the reader to ramfs-rootfs-initramfs.rst documentation for more
details

Signed-off-by: Ann Yun <by.ann.yun@gmail.com>
---
V2 -> V3: Fix the styling error (trailing whitespace)
V1 -> V2: Mention Documentation/filesystems/ramfs-rootfs-initramfs.rst

 Documentation/arch/openrisc/openrisc_port.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/arch/openrisc/openrisc_port.rst b/Documentation/arch/openrisc/openrisc_port.rst
index a8f307a3b499..60b0a9e51d70 100644
--- a/Documentation/arch/openrisc/openrisc_port.rst
+++ b/Documentation/arch/openrisc/openrisc_port.rst
@@ -40,6 +40,12 @@ Build the Linux kernel as usual::
 	make ARCH=openrisc CROSS_COMPILE="or1k-linux-" defconfig
 	make ARCH=openrisc CROSS_COMPILE="or1k-linux-"
 
+If you want to embed initramfs in the kernel, also pass ``CONFIG_INITRAMFS_SOURCE``. For example::
+
+	make ARCH=openrisc CROSS_COMPILE="or1k-linux-" CONFIG_INITRAMFS_SOURCE="path/to/rootfs path/to/devnodes"
+
+For more information on this, please check Documentation/filesystems/ramfs-rootfs-initramfs.rst.
+
 3) Running on FPGA (optional)
 
 The OpenRISC community typically uses FuseSoC to manage building and programming
-- 
2.37.2