generic: filter: add RUSTC symbols

These symbols depend on rustc version and is autodetected and set, so make
sure to filter them out.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>

target/linux/generic/config-filter

@@ -17,6 +17,10 @@ CONFIG_PAHOLE_HAS_LANG_EXCLUDE=.*
 CONFIG_PAHOLE_HAS_SPLIT_BTF=.*
 CONFIG_PAHOLE_VERSION=.*
 CONFIG_PLUGIN_HOSTCC=".*"
+CONFIG_RUSTC_HAS_COERCE_POINTEE=.*
+CONFIG_RUSTC_HAS_FILE_AS_C_STR=.*
+CONFIG_RUSTC_HAS_FILE_WITH_NUL=.*
+CONFIG_RUSTC_HAS_SPAN_FILE=.*
 CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES=.*
 CONFIG_RUSTC_LLVM_VERSION=.*
 CONFIG_RUSTC_SUPPORTS_.*=.*