video/rockchip: rga2: fix rga crash with high memory

video/rockchip: rga2: fix rga crash with high memory

phys_to_virt not support highmem.

[   38.247986] Unable to handle kernel paging request at virtual address 20857000
[   38.306701] pgd = ed418000
[   38.309505] [20857000] *pgd=00000000
[   38.313118] Internal error: Oops: 2805 [#1] PREEMPT SMP ARM
[   38.318682] Modules linked in:
[   38.321746] CPU: 2 PID: 1410 Comm: DisplayThread Not tainted 4.4.55 #156
[   38.328435] Hardware name: Rockchip (Device Tree)
[   38.333131] task: dd2ad480 ti: dcc08000 task.ti: dcc08000
[   38.338527] PC is at v7_dma_flush_range+0x1c/0x34
[   38.343225] LR is at rga_dma_flush_range+0x30/0x68
[   39.215229] [<c0117440>] (v7_dma_flush_range) from [<c03f969c>] (rga_dma_flush_range+0x30/0x68)
[   39.223918] [<c03f969c>] (rga_dma_flush_range) from [<c03f98f4>] (rga2_MapUserMemory+0x220/0x2b0)
[   39.232777] [<c03f98f4>] (rga2_MapUserMemory) from [<c03f9bd4>] (rga2_set_mmu_info+0x1bc/0x928)
[   39.241461] [<c03f9bd4>] (rga2_set_mmu_info) from [<c03f8930>] (rga2_blit+0x2f4/0x448)
[   39.249366] [<c03f8930>] (rga2_blit) from [<c03f8ae8>] (rga2_blit_sync+0x64/0x1b0)
[   39.256923] [<c03f8ae8>] (rga2_blit_sync) from [<c03f91dc>] (rga_ioctl+0x4d0/0x6d8)
[   39.264570] [<c03f91dc>] (rga_ioctl) from [<c023ea58>] (do_vfs_ioctl+0x564/0x6a0)
[   39.272042] [<c023ea58>] (do_vfs_ioctl) from [<c023ebe0>] (SyS_ioctl+0x4c/0x74)
[   39.279342] [<c023ebe0>] (SyS_ioctl) from [<c0107180>] (ret_fast_syscall+0x0/0x3c)

Change-Id: I81fe2d108932a96414a2822c1329c4335753d1d9
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>