efi_selftest: remove unnecessary __efi_runtime_data attribute

Assigning a single variable to section __efi_runtime_date while the rest of
the test is in the boottime section does not make much sense.

As we do not set a virtual address map here, we don't need a runtime
section.

Update the variables at runtime test.

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

lib/efi_selftest/efi_selftest_variables_runtime.c

@@ -17,8 +17,7 @@
 #define EFI_ST_MAX_VARNAME_SIZE 40
 
 static const efi_guid_t guid_vendor0 = EFI_GLOBAL_VARIABLE_GUID;
-static const efi_guid_t __efi_runtime_data efi_rt_var_guid =
-	U_BOOT_EFI_RT_VAR_FILE_GUID;
+static const efi_guid_t efi_rt_var_guid = U_BOOT_EFI_RT_VAR_FILE_GUID;
 
 /**
  * execute() - execute unit test