[PATCH 1/1] Avoid ambiguity in calling atom_add functions.

clang (since r280553) allows pointer casts in function overloads,
so we need to disambiguate the second argument.

clang might be smarter about overloads in the future
(see ⚙ D24113 Allow implicit conversions between incompatible pointer types in overload resolution in C.), but let's be safe in libclc anyway.

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

Reviewed-by: Vedran Miletić <vedran@miletic.net>

clang (since r280553) allows pointer casts in function overloads,
so we need to disambiguate the second argument.

LGTM.