broadcom/simulator: use string copy instead of memcpy

Using memcpy with the max size generates a global-buffer-overflow, as
the performance counter strings are smaller than the max size.

Instead, use a string copy function to get a copy.

This was detected with address sanitizer enabled and running vulkaninfo.

Fixes: 3e8b2fe053a ("broadcom/simulator: Add DRM_IOCTL_V3D_GET_COUNTER to simulator")
Reviewed-by: Jose Maria Casanova Crespo <jmcasanova@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33627>
1 file changed