arm64: defconfig: Enable Qualcomm Command DB driver

arm64: defconfig: Enable Qualcomm Command DB driver

The Qualcomm Command DB driver seems to have been indirectly enabled by
the Qualcomm DRM driver and up until the introduction of '778279f4f5e4
("soc: qcom: cmd-db: allow loading as a module")' this resulted in the
driver "always" being builtin on arm64. But with the introduction of
said change it, and all other RPMH related drivers, becomes =m.

The immediate result is that the uart driver fails to probe, which
depending on userspace's dependency on the presence of /dev/console
might be fatal. For systems getting past this the default timeout of 0
seconds for probe deferral of many subsystems causes the system to be
completely useless.

So, make Command DB builtin.

Reviewed-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20201103010850.757500-1-bjorn.andersson@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>