Revert "Staging: panel: usleep_range is preferred over udelay"

Revert "Staging: panel: usleep_range is preferred over udelay"

commit b64a1cbef6df47c986ad622b5b2e4d3d1940070c upstream.

This reverts commit ebd43516d3879f882a403836bba8bc5791f26a28.

We should not be sleeping inside spin_lock.

Fixes: ebd43516d387 ("Staging: panel: usleep_range is preferred over udelay")
Cc: Sirnam Swetha <theonly.ultimate@gmail.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Reported-by: Huang, Ying <ying.huang@intel.com>
Tested-by: Huang, Ying <ying.huang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>