This patch add PPMUs (Platform Performance Monitoring Unit) dt node
for Exynos4 (Exynos4210/4212/4412) SoCs. PPMU dt node is used for
monitor the utilization of each IP.

The Exynos4210/Exynos4212/Exynos4412 SoC includes following PPMUs:
- PPMU_DMC0      0x106A_0000
- PPMU_DMC1      0x106B_0000
- PPMU_CPU       0x106C_0000
- PPMU_ACP       0x10AE_0000
- PPMU_RIGHT_BUS 0x112A_0000
- PPMU_LEFT_BUS  0x116A_0000
- PPMU_FSYS      0x1263_0000
- PPMU_LCD0      0x11E4_0000
- PPMU_CAMIF     0x11AC_0000
- PPMU_IMAGE     0x12AA_0000
- PPMU_TV        0x12E4_0000
- PPMU_3D        0x1322_0000
- PPMU_MFC_LEFT  0x1366_0000
- PPMU_MFC_RIGHT 0x1367_0000

Additionally, the Exynos4210 SoC includes following PPMUs:
- PPMU_LCD1      0x1224_0000
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>