Added comments : gic.c, gic.h
Merge pull request #138 from joohyun0115/v1

sched : refactor scheduler feature
Merge branch 'v1' of https://github.com/kesl/khypervisor into v1
Merge pull request #139 from joohyun0115/v1

Refactor trap relative functions
Merge branch 'v1' of https://github.com/kesl/khypervisor into v1
Added comments : gic, virq, virqmap
Refactor : GIC feature, VIRQ map macro, guest context init
Fixed styling cfg_platform.h
Merge pull request #142 from in1004kyu/v1

Added comments : gic, virq, virqmap, Refactor : GIC feature, VIRQ map macro, guest context init