libc: newlib: hooks: correct signature for open()

The function signature for open() in libc-hooks.c was
incorrect. Additionally, the ALIAS_OF() macro causes a
compile error, because it simplifies the open function
signature to int open(), which is a conflicting
definition.

Use the correct definition to get around compile errors.

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>

Author: cfriedt

lib/libc/newlib/libc-hooks.c

@@ -243,7 +243,7 @@ int _open(const char *name, int flags, ...)
 {
 	return -1;
 }
-__weak FUNC_ALIAS(_open, open, int);
+__weak int open(const char *name, int mode, ...) ALIAS_OF(_open);
 
 int _close(int file)
 {