[ARM] PR68532: Fix up vuzp for big endian

gcc/ChangeLog:

2016-02-09  Charles Baylis  <charles.baylis@linaro.org>

       PR target/68532
       * config/arm/arm.c (neon_endian_lane_map): New function.
       (neon_vector_pair_endian_lane_map): New function.
       (arm_evpc_neon_vuzp): Allow for big endian lane order.
       * config/arm/arm_neon.h (vuzpq_s8): Adjust shuffle patterns for big
       endian.
       (vuzpq_s16): Likewise.
       (vuzpq_s32): Likewise.
       (vuzpq_f32): Likewise.
       (vuzpq_u8): Likewise.
       (vuzpq_u16): Likewise.
       (vuzpq_u32): Likewise.
       (vuzpq_p8): Likewise.
       (vuzpq_p16): Likewise.

gcc/testsuite/ChangeLog:
2016-02-09  Charles Baylis  <charles.baylis@linaro.org>

       PR target/68532
       * gcc.c-torture/execute/pr68532.c: New test.

From-SVN: r233251