core/bitXXgen: Use explicit cast of void* to uint8_t

Turns out we use this header in C++ code ...

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/include/osmocom/core/bitXXgen.h.tpl b/include/osmocom/core/bitXXgen.h.tpl
index 35f26db..5fa2bb7 100644
--- a/include/osmocom/core/bitXXgen.h.tpl
+++ b/include/osmocom/core/bitXXgen.h.tpl
@@ -56,10 +56,11 @@
  *  \param[out] p Buffer to store integer
  *  \param[in] n Number of bytes to store
  */
-static inline void osmo_storeXXle_ext(uintXX_t x, uint8_t *p, uint8_t n)
+static inline void osmo_storeXXle_ext(uintXX_t x, void *p, uint8_t n)
 {
 	uint8_t i;
-	for(i = 0; i < n; p[i] = (x >> i * 8) & 0xFF, i++);
+	uint8_t *q = (uint8_t *)p;
+	for(i = 0; i < n; q[i] = (x >> i * 8) & 0xFF, i++);
 }
 
 /*! \brief store unaligned n-byte integer (big-endian encoding) into uintXX_t
@@ -67,10 +68,11 @@
  *  \param[out] p Buffer to store integer
  *  \param[in] n Number of bytes to store
  */
-static inline void osmo_storeXXbe_ext(uintXX_t x, uint8_t *p, uint8_t n)
+static inline void osmo_storeXXbe_ext(uintXX_t x, void *p, uint8_t n)
 {
 	uint8_t i;
-	for(i = 0; i < n; p[i] = (x >> ((n - 1 - i) * 8)) & 0xFF, i++);
+	uint8_t *q = (uint8_t *)p;
+	for(i = 0; i < n; q[i] = (x >> ((n - 1 - i) * 8)) & 0xFF, i++);
 }