Always enable feature critical-section-single-core of cortex-m

Cargo.toml

@@ -29,7 +29,7 @@ members = [".", "testsuite", "codegen"]
 [dependencies]
 bxcan = { version = "0.7.0", optional = true }
 cfg-if = "1.0.0"
-cortex-m = "0.7.7"
+cortex-m = { version = "0.7.7", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7.3"
 critical-section = "1.1.2"
 defmt = { version = ">=0.2.3, <0.4.0", optional = true }
@@ -46,7 +46,6 @@ stm32f3 = { version = "0.16.0", package = "stm32f3-staging", default-features =
 void = { version = "1.0.2", default-features = false }
 
 [dev-dependencies]
-cortex-m = { version = "0.7.7", features = ["critical-section-single-core"] }
 cortex-m-rtic = "1.1"
 cortex-m-semihosting = "0.5.0"
 defmt = "0.3.5"