Get rid of the eir struct mips_fpu_emulator_private member. It's

Get rid of the eir struct mips_fpu_emulator_private member.  It's
never initialized been initialized anywhere, just saved to and
restored from signal frames so nonsense anyway.  As neat side effect
of being shared between all processors it was also abusable as a
nice covert channel between processes.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>