[portability] compile error on non-x86

[varkappadev]

Describe the bug
src/storage/seg/hashtable.c unconditionally includes x86intrin.h and thus fails to compile on non-x86

To Reproduce
compile as per build instructions, make -j fails

Expected behavior
builds successfully

Environment
macOS 12.1 (arm64, i.e. M1) with Homebrew clang version 13.0.0

Additional context
feel free to close (but please update the requirements in README.md) if pelikan is only intended for x86_64

Thanks!

[1a1a11a]

we will remove the include because it is not needed, thank you for pointing out

[thinkingfish]

#444

[thinkingfish]

Please reopen if other things are in the way.