FROMLIST: kbuild: rust: make command for RUSTC_VERSION_TEXT closer to the CC one

`CC_VERSION_TEXT` is defined as:

    CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))

Make `RUSTC_VERSION_TEXT` closer to that, i.e. add `LC_ALL=C` and `|
head -n 1` in case it matters in the future, and for consistency.

This reduces the difference in the next commit.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Link: https://lore.kernel.org/r/20240808221138.873750-3-ojeda@kernel.org
Change-Id: Iad713ad25e917e2ae480b5c5b290b729d0fdec8c
Signed-off-by: Alice Ryhl <aliceryhl@google.com>

Author: ojeda

init/Kconfig

@@ -1930,7 +1930,7 @@ config RUST
 config RUSTC_VERSION_TEXT
 	string
 	depends on RUST
-	default "$(shell,$(RUSTC) --version 2>/dev/null)"
+	default "$(shell,LC_ALL=C $(RUSTC) --version 2>/dev/null | head -n 1)"
 
 config BINDGEN_VERSION_TEXT
 	string