Remove some math_private.h libc_feholdexcept_setround overrides.

Remove some math_private.h libc_feholdexcept_setround overrides.

math_private.h headers for configurations lacking support for
floating-point exceptions and rounding modes define
libc_feholdexcept_setround to override the default version with one
that discards its rounding mode argument.

Unlike other such libc_fe* macros that I removed, this one is actually
used for such configurations (in dbl-64/e_sqrt.c).  However, this does
not make the macro required.  It's only used for such configurations
with FE_TONEAREST as the rounding mode (anything needing another mode
should not be used when that mode is unavailable), and the default
definition just calls __feholdexcept and __fesetround.  Since we now
have suitable inline do-nothing definitions of __feholdexcept and
__fesetround for the cases of no exceptions and rounding modes, we can
just rely on those inlines to achieve the same optimization as this
macro definition.  Thus, this patch removes those macro definitions
(and the math_private.h headers containing them, when no longer needed
after that removal).

Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by the patch.

	* sysdeps/m68k/coldfire/fpu/math_private.h: Move to ....
	* sysdeps/m68k/coldfire/math_private.h: ... here.
	* sysdeps/m68k/coldfire/nofpu/math_private.h: Remove file.
	* sysdeps/tile/math_private.h: Likewise.
	* sysdeps/microblaze/math_private.h (libc_feholdexcept_setround):
	Remove macro.
	* sysdeps/nios2/math_private.h (libc_feholdexcept_setround):
	Likewise.