x86/resctrl: Remove redundant assignment to variable chunks

The variable chunks is being shifted right and re-assinged the shifted
value which is then returned. Since chunks is not being read afterwards
the assignment is redundant and the >>= operator can be replaced with a
shift >> operator instead.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lkml.kernel.org/r/20211207223735.35173-1-colin.i.king@gmail.com