powerpc/math-emu: Fix decoding of some instructions

The decoding of some instructions such as fsqrt{s} was incorrect,
using the wrong registers, and thus could not work.

This fixes it and also adds a couple of place holders for missing
instructions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/math-emu/fre.c

@@ -0,0 +1,11 @@
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/uaccess.h>
+
+int fre(void *frD, void *frB)
+{
+#ifdef DEBUG
+	printk("%s: %p %p\n", __func__, frD, frB);
+#endif
+	return -ENOSYS;
+}