fix misordered syscall arguments for posix_fadvise on arm

the arm version of the syscall has a custom argument ordering to avoid
needing a 7-argument syscall due to 64-bit argument alignment.
diff --git a/src/fcntl/arm/posix_fadvise.c b/src/fcntl/arm/posix_fadvise.c
new file mode 100644
index 0000000..5c52f6b
--- /dev/null
+++ b/src/fcntl/arm/posix_fadvise.c
@@ -0,0 +1,12 @@
+#include <fcntl.h>
+#include "syscall.h"
+#include "libc.h"
+
+int posix_fadvise(int fd, off_t base, off_t len, int advice)
+{
+	/* ARM-specific syscall argument order */
+	return -__syscall(SYS_fadvise, fd, advice,
+		__SYSCALL_LL_E(base), __SYSCALL_LL_E(len));
+}
+
+LFS64(posix_fadvise);