Fix a bug that the size of a gate descriptor in the IDT is 8 bytes. The size is 8 bytes in 32-bit mode, while it is 16 bytes in 64-bit mode. Replace the hard-coded size with a sizeof.
Fix a bug that the size of a gate descriptor in the IDT is 8 bytes. The size is 8 bytes in 32-bit mode, while it is 16 bytes in 64-bit mode. Replace the hard-coded size with a sizeof.

git-svn-id: 5648d1bec6962b0a6d1d1b40eba8cf5cdb62da3d@11177 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2