Documentation: arm: Add bootargs to the table of added DT parameters

The bootargs node is also added by the EFI stub in the function
update_fdt(), so add it to the table.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Song Shuai <songshuaishuai@tinylab.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230817130734.10387-1-alexghiti@rivosinc.com

Documentation/arch/arm/uefi.rst

@@ -50,7 +50,7 @@ The stub populates the FDT /chosen node with (and the kernel scans for) the
 following parameters:
 
 ==========================  ======   ===========================================
-Name                        Size     Description
+Name                        Type     Description
 ==========================  ======   ===========================================
 linux,uefi-system-table     64-bit   Physical address of the UEFI System Table.
 
@@ -67,4 +67,6 @@ linux,uefi-mmap-desc-ver    32-bit   Version of the mmap descriptor format.
 
 kaslr-seed                  64-bit   Entropy used to randomize the kernel image
                                      base address location.
+
+bootargs                    String   Kernel command line
 ==========================  ======   ===========================================