doc: describe generation of SMBIOS table

SMBIOS is not x86 specific. So we should have an architecture independent
page describing it.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/doc/arch/x86.rst b/doc/arch/x86.rst
index 5494155..634387a 100644
--- a/doc/arch/x86.rst
+++ b/doc/arch/x86.rst
@@ -732,7 +732,7 @@
 To generate SMBIOS tables in U-Boot, for use by the OS, enable the
 CONFIG_GENERATE_SMBIOS_TABLE option. The easiest way to provide the values to
 use is via the device tree. For details see
-device-tree-bindings/sysinfo/smbios.txt
+:download:`smbios.txt <../device-tree-bindings/sysinfo/smbios.txt>`.
 
 TODO List
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