Add some missing features found by cargo-hack (#2571)

Small things that fix scenarios we don't hit in CI.

Author: smalis-msft

tmk/tmk_macros/Cargo.toml

@@ -11,7 +11,7 @@ proc-macro = true
 
 [dependencies]
 quote.workspace = true
-syn.workspace = true
+syn = { workspace = true, features = [ "full" ] }
 
 [lints]
 workspace = true

vm/devices/firmware/uefi_nvram_storage/Cargo.toml

@@ -10,7 +10,7 @@ rust-version.workspace = true
 default = []
 
 inspect = ["dep:inspect", "uefi_specs/inspect"]
-save_restore = ["inspect", "dep:mesh_protobuf", "dep:vmcore"]
+save_restore = ["inspect", "dep:mesh_protobuf", "dep:vmcore", "guid/mesh"]
 
 [dependencies]
 guid.workspace = true

vm/loader/igvmfilegen_config/Cargo.toml

@@ -7,7 +7,7 @@ edition.workspace = true
 rust-version.workspace = true
 
 [dependencies]
-serde = { workspace = true, features = ["derive"] }
+serde = { workspace = true, features = ["std", "derive"] }
 
 [dev-dependencies]
 serde_json = { workspace = true, features = ["std"] }