davinci: cpufreq: fix section mismatch warning

Fix below section mismatch warning:
WARNING: vmlinux.o(.data+0x673c): Section mismatch in reference from the variable davinci_driver to the function .init.text:davinci_cpu_init()
The variable davinci_driver references
the function __init davinci_cpu_init()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console,

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>