crosssdk/nativesdk: Ensure EXTRA_OECONF_FPU is unset

crosssdk/nativesdk: Ensure EXTRA_OECONF_FPU is unset

If EXTRA_OECONF_FPU is left set, certain ARM variables related to hard-float
can get pulled in and trigger rebuilds of the crosssdk code. The best solution
is to simply force the variable to a known correct value for the SDK targets
currently supported in the same way as TARGET_FPU.

There is some slight rearrangement of the gcc code to ensure the variable is
always used to call the fpu function.

(From OE-Core rev: 410990445ada8cdcfaec4e6fa5791cee9a5b8983)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>