radeon: fix printf format specifier.

From glibc printf(3):

Z      A nonstandard synonym for z that predates the appearance of z.
       Do not use in new code.

Z may not exist on non-glibc systems. Prefer the standard symbol.

Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
1 file changed