smbios: Allow compilation on 64bit systems

smbios: Allow compilation on 64bit systems

The SMBIOS generation code passes pointers as u32. That causes the compiler
to warn on casts to pointers. This patch moves all address pointers to
uintptr_t instead.

Technically u32 would be enough for the current SMBIOS2 style tables, but
we may want to extend the code to SMBIOS3 in the future which is 64bit
address capable.

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>