ec/lenovo: Add guards to fix build errors without SMBIOS

Not selecting the Kconfig option `GENERATE_SMBIOS_TABLES` the build
fails with the error below.

```
    CC         ramstage/ec/lenovo/h8/h8.o
src/ec/lenovo/h8/h8.c:201:2: error: unknown field 'get_smbios_strings' specified in initializer
  .get_smbios_strings = h8_smbios_strings,
  ^
src/ec/lenovo/h8/h8.c:201:2: error: initialization from incompatible pointer type [-Werror]
src/ec/lenovo/h8/h8.c:201:2: error: (near initialization for 'h8_dev_ops.read_resources') [-Werror]
cc1: all warnings being treated as errors
```

So add the appropriate preprocessor guards to fix the build error.

Change-Id: I3baed452d422539a805c628a8c4a6a8c2a809317
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: https://review.coreboot.org/17770
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

0 files changed, 0 insertions, 0 deletions