arm: samsung: remove pixclock from several boards

Since "s3c-fb: Automatically calculate pixel clock when none is given",
there's no need for manually calculating the pixel clock anymore so remove
these lines and add the correct refresh rate where appropriately.

Signed-off-by: Maurus Cuelenaere <mcuelenaere@gmail.com>
Cc: Pawel Osciak <p.osciak@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: InKi Dae <inki.dae@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>