BaseSynchronizationLib: Fix RISC-V helper name

BaseSynchronizationLib: Fix RISC-V helper name

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4143

Fix the name of InternalSyncCompareExchange64() function.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reported-by: Zhihao Li <zhihao.li@intel.com>
Tested-by: Zhihao Li <zhihao.li@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Daniel Schaefer <git@danielschaefer.me>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>