This patch fixes a few issues when detecting which kernel_fpu functions
are available.
- Use kernel_fpu_begin() if it's exported on newer kernels.
- Use ZFS_LINUX_TRY_COMPILE_SYMBOL() to choose the right kernel_fpu
function when using --enable-linux-builtin.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Closes#8259Closes#8363