GCC generates slow ia32 code for FLAC__lpc_restore_signal_wide() and
FLAC__lpc_compute_residual_from_qlp_coefficients_wide() so 24-bit
encoding/decoding is slower for GCC compile than for MSVS or ICC
compile. This patch adds ia32 asm versions of these functions.

Patch-from: lvqcl <lvqcl.mail@gmail.com>