clk: samsung: exynos5260: Move struct samsung_cmu_info to init section

This patch moves the samsung_cmu_info struct instances to initconst
section, this decreases the kernel image size by 784 bytes, which makes
zImage smaller by 480 bytes.

The patch increases .init.rodata section size by 780 bytes but decreases
.init.text section size by 1564 bytes.

Size of the drivers/clk/samsung/clk-exynos5260.o object file is 29100
bytes without the patch and 28316 after applying the patch.

The section size differences are as below:
15c15
<   3 .init.text    000006b8  00000000  00000000  00000034  2**2
---
>   3 .init.text    0000009c  00000000  00000000  00000034  2**2
25c25
<   8 .init.rodata  00003f6c  00000000  00000000  00002f20  2**2
---
>   8 .init.rodata  00004278  00000000  00000000  00002904  2**2

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>