soc: qcom: scm-xpu: add support for XPU errors that are fatal by default

The existing scm-xpu implementation makes an unconditional scm
call at boot. The assumption was that such errors would be non-
fatal by default, and so a desired behavior could be achieved
by controlling whether the driver was compiled.

On recent targets like msm8996, XPU errors are treated as
fatal by default. To support cases where it may be desirable
to treat them as non-fatal, the driver must be changed to
make the appropriate scm call based on a new Kconfig choice.

Change-Id: Ibb55c062937f130c13538f049582575d9a6f52ad
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>