soc: litex: Add function for reading 64bit CSRs

This adds a helper function for reading LiteX 64-bit CSRs
to be used by LiteX drivers.

Signed-off-by: Jakub Cebulski <jcebulski@internships.antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
1 file changed