hw/arm/exynos: Convert fprintf to qemu_log_mask/error_report

hw/arm/exynos: Convert fprintf to qemu_log_mask/error_report

qemu_log_mask() and error_report() are preferred over fprintf() for
logging errors.  Also remove square brackets [] and additional new line
characters in printed messages.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-id: 20170313184750[email protected]
[PMM: wrapped long line]
Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>