Remove duplicate static_asserts

One should be enough. Can be reviewed with
--color-moved=dimmed-zebra --color-moved-ws=ignore-all-space

Author: MarcoFalke

src/arith_uint256.h

@@ -24,22 +24,19 @@ template<unsigned int BITS>
 class base_uint
 {
 protected:
+    static_assert(BITS / 32 > 0 && BITS % 32 == 0, "Template parameter BITS must be a positive multiple of 32.");
     static constexpr int WIDTH = BITS / 32;
     uint32_t pn[WIDTH];
 public:
 
     base_uint()
     {
-        static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
-
         for (int i = 0; i < WIDTH; i++)
             pn[i] = 0;
     }
 
     base_uint(const base_uint& b)
     {
-        static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
-
         for (int i = 0; i < WIDTH; i++)
             pn[i] = b.pn[i];
     }
@@ -53,8 +50,6 @@ class base_uint
 
     base_uint(uint64_t b)
     {
-        static_assert(BITS/32 > 0 && BITS%32 == 0, "Template parameter BITS must be a positive multiple of 32.");
-
         pn[0] = (unsigned int)b;
         pn[1] = (unsigned int)(b >> 32);
         for (int i = 2; i < WIDTH; i++)