providers/implementations/kdfs/argon2.c: Don't use UINT64_C

providers/implementations/kdfs/argon2.c: Don't use UINT64_C

With less than C99 compilers, this macro isn't guaranteed to exist, and
the value passed to it is 32 bits, so explicitly ending it with 'UL' is
correct in all cases.  We simply leave it to the compiler to extend it
appropriately for uint64_t.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20547)