Input: spear_keyboard - use correct io accessors

All SPEAr keyboard registers are 32 bit wide and are word aligned. This
patch aligns all io access to be word size using relaxed version of
readl/writel.

Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>