virgl: fix build failure and fix false tabs to spaces

1st commit fixes build failure without egl. e.g. when

meson setup out -Dplatforms= -Dvenus=true

Fixes: 287f8ecb ("vrend: Import blob resource")

2nd commit fixes false tabs to spaces. I started from tabs around the 1st commit fix, and ended up doing a purge..there're still existing align issues in some places but I'd defer until clang-format is enforced globally

/cc @gerddie @tintou