gf_vect_mul_sve: fix error for not aligned len

[liuqinfei]

fix #268

# With this Patch:
[root@localhost isa-l]# make check
make --no-print-directory check-am
make --no-print-directory erasure_code/gf_vect_mul_test erasure_code/erasure_code_test erasure_code/gf_inverse_test erasure_code/erasure_code_update_test raid/xor_gen_test raid/pq_gen_test raid/xor_check_test raid/pq_check_test crc/crc16_t10dif_test crc/crc16_t10dif_copy_test crc/crc64_funcs_test crc/crc32_funcs_test igzip/igzip_rand_test igzip/igzip_wrapper_hdr_test igzip/checksum32_funcs_test mem/mem_zero_detect_test
  CCLD     erasure_code/gf_vect_mul_test
  CCLD     erasure_code/erasure_code_test
  CCLD     erasure_code/gf_inverse_test
  CCLD     erasure_code/erasure_code_update_test
  CCLD     raid/xor_gen_test
  CCLD     raid/pq_gen_test
  CCLD     raid/xor_check_test
  CCLD     raid/pq_check_test
  CCLD     crc/crc16_t10dif_test
  CCLD     crc/crc16_t10dif_copy_test
  CCLD     crc/crc64_funcs_test
  CCLD     crc/crc32_funcs_test
  CCLD     igzip/igzip_rand_test
  CCLD     igzip/igzip_wrapper_hdr_test
  CCLD     igzip/checksum32_funcs_test
  CCLD     mem/mem_zero_detect_test
make --no-print-directory check-TESTS
PASS: erasure_code/gf_vect_mul_test
PASS: erasure_code/erasure_code_test
PASS: erasure_code/gf_inverse_test
PASS: erasure_code/erasure_code_update_test
PASS: raid/xor_gen_test
PASS: raid/pq_gen_test
PASS: raid/xor_check_test
PASS: raid/pq_check_test
PASS: crc/crc16_t10dif_test
PASS: crc/crc16_t10dif_copy_test
PASS: crc/crc64_funcs_test
PASS: crc/crc32_funcs_test
PASS: igzip/igzip_rand_test
PASS: igzip/igzip_wrapper_hdr_test
PASS: igzip/checksum32_funcs_test
PASS: mem/mem_zero_detect_test
============================================================================
Testsuite summary for libisal 2.30.0
============================================================================
# TOTAL: 16
# PASS:  16
# SKIP:  0
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0
============================================================================

[pablodelara]

Thanks @liuqinfei for this PR, fixing the issue. Since I merged the PR disabling that test case for ARM, could you rebase this PR and remove the check for ARM, so it is also enabled? Thanks!

[liuqinfei]

Thanks @liuqinfei for this PR, fixing the issue. Since I merged the PR disabling that test case for ARM, could you rebase this PR and remove the check for ARM, so it is also enabled? Thanks!

I have updated the PR and enable the unit tests for ARM again. Please check. Thanks.

[pablodelara]

Code merged, thanks!