arm:samsung:trats:fix: Restore proper orientation of TRATS's LCD panel

Before setting: mipi_lcd_device.reverse_panel = 1, the Trats's LCD panel
was flipped by 180 degrees.

The flip was caused by following change:
Exynos: Change get_timer() to work correctly
SHA1: 3d00c0cb

This commit fixed udelay(), which is necessary (due to HW LCD controller
oddity) for mipi-dsi correct operation. As a result the display orientation
has been switched.

As a follow up, the hwrevision() function has been removed, since it was
used only in this particular place.

Test HW: Trats Exynos4210 rev 0.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Acked-by: Minkyu Kang <mk7.kang@samsung.com>