test: add a check for FE_DIVBYZERO

Some architectures, such as Microblaze and Nios2, currently do not
implement FE_DIVBYZERO, even though they have <fenv.h> and
feenableexcept(). This commit adds a configure.ac check to verify
whether FE_DIVBYZERO is defined or not, and if not, disables the
problematic code in test/utils.c.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>