fix(imx8ulp): fix variable may be used uninitialized error

When building with LTO, the compiler discovers that it is possible to
use the `volt` variable without writing to it. This happens when
upower_pmic_i2c_read() returns error. Check its return value and panic()
if something went wrong so the error doesn't propagate silently.

Change-Id: I46d460892a2eb24596373ad7a5b07f730a0753de
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
1 file changed