Port of a Linux commit 6995de2

  Replace a division by 2 operation for a right shift rotation of 1 bit.

  Probably any recent and decent compiler does this kind of substitution
  in order to improve code performance. Nevertheless it's a coding good
  practice whenever there is a division / multiplication by multiple of 2
  to replace it by the equivalent operation in this case, the shift
  rotation.

  Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
  Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
  Acked-by: Jingoo Han <jingoohan1@gmail.com>
  Acked-by: Joao Pinto <jpinto@synopsys.com>

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>