Omap35xxPkg: drop CpuExceptionHandlerLib library class resolution

Omap35xxPkg: drop CpuExceptionHandlerLib library class resolution

Remove the null resolution for CpuExceptionHandlerLib: this version will
no longer work once we update ARM's CpuDxe to depend on the ARM specific
version. Since this module does not actually rely on it, let's just remove
all mention of it.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Eugene Cohen <eugene@hp.com>