ARM: davinci: cp-intc: use readl/writel_relaxed()

Replace all calls to __raw_readl() & __raw_writel() with readl_relaxed()
and writel_relaxed() respectively. It's safe to do as there's no
endianness conversion being done in the code.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>