Add rocshmem_int64_p (#335)

docs/api/rma.rst

@@ -218,7 +218,7 @@ The following table lists the supported RMA data types:
       - No
     * - int64_t
       - int64
-      - No
+      - Yes
     * - uint8_t
       - uint8
       - No

include/rocshmem/rocshmem_RMA.hpp

@@ -405,6 +405,11 @@ __host__ void rocshmem_ctx_ulonglong_p(
 __host__ void rocshmem_ulonglong_p(
     unsigned long long *dest, unsigned long long value, int pe);
 
+__device__ ATTR_NO_INLINE void rocshmem_ctx_int64_p(
+    rocshmem_ctx_t ctx, unsigned long long *dest, unsigned long long value,
+    int pe);
+__device__ ATTR_NO_INLINE void rocshmem_int64_p(
+    unsigned long long *dest, unsigned long long value, int pe);
 
 /**
  * @name SHMEM_GET