soc/tegra: fuse: Fix spurious straps warning on SMCCC platforms

soc/tegra: fuse: Fix spurious straps warning on SMCCC platforms

My Grace host started to show this warning:
  WARNING: drivers/soc/tegra/fuse/tegra-apbmisc.c:120 at tegra_read_straps
   tegra30_fuse_add_randomness
   tegra30_fuse_init
   tegra_fuse_probe

tegra_read_straps() warns when the static "chipid" cache is still zero,
using it as a proxy for "APBMISC has been initialised". However chipid
is only ever populated lazily by tegra_read_chipid() when it reads the
APBMISC register.

Guard on apbmisc_base instead, which is set unconditionally in
tegra_init_apbmisc_resources() for all platforms and is already the
sentinel used by tegra_read_chipid().

Fixes: 8b8ee2e56f95 ("soc/tegra: Use ARM SMCCC to get chip ID, revision, and platform info")
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>