trace: fix printk warning for u64

A powerpc ppc64_defconfig build produces these warnings:

kernel/trace/ring_buffer.c: In function 'rb_add_time_stamp':
kernel/trace/ring_buffer.c:969: warning: format '%llu' expects type 'long long unsigned int', but argument 2 has type 'u64'
kernel/trace/ring_buffer.c:969: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type 'u64'
kernel/trace/ring_buffer.c:969: warning: format '%llu' expects type 'long long unsigned int', but argument 4 has type 'u64'

Just cast the u64s to unsigned long long like we do everywhere else.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>