CLK: SPEAr: Remove unused dummy apb_pclk

Dummy clocks were added for ARM platforms, so that clk_get() for interface clk
doesn't fail for amba devices from amba_probe(). Because there is no amba device
for SPEAr that doesn't have a valid clock with dev_id for SPEAr, we don't need
these dummy clocks. Hence, remove them.

Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>