kselftest/arm64: mte: use string literal for printf-style functions

Using pointers for the format specifier strings in printf-style
functions can create potential security problems, as the number of
arguments to be parsed could vary from call to call. Most compilers
consequently warn about those:
"format not a string literal and no format arguments [-Wformat-security]"

If we only want to print a constant string, we can just use a fixed "%s"
format instead, and pass the string as an argument.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240816153251.2833702-5-andre.przywara@arm.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>