hwrng: mxc-rnga - Adapt clocks to new i.mx clock framework

Adapt clocks to the new i.mx clock framework and fix the following warning:

------------[ cut here ]------------
WARNING: at drivers/clk/clk.c:511 __clk_enable+0x9c/0xac()
Modules linked in:
Backtrace:
[<800124c8>] (dump_backtrace+0x0/0x10c) from [<804172dc>] (dump_stack+0x18/0x1c)
 r7:00000009 r6:000001ff r5:8032cb50 r4:00000000
[<804172c4>] (dump_stack+0x0/0x1c) from [<80021834>] (warn_slowpath_common+0x54)
[<800217e0>] (warn_slowpath_common+0x0/0x6c) from [<80021870>] (warn_slowpath_n)
 r9:80581cac r8:8700a9c0 r7:805ab070 r6:80000013 r5:806133d4
r4:8700a9c0
[<8002184c>] (warn_slowpath_null+0x0/0x2c) from [<8032cb50>] (__clk_enable+0x9c)
[<8032cab4>] (__clk_enable+0x0/0xac) from [<8032cb88>] (clk_enable+0x28/0x44)
 r5:806133d4 r4:8700a9c0
[<8032cb60>] (clk_enable+0x0/0x44) from [<80560f14>] (mxc_rnga_probe+0x68/0x164)
 r7:805ab070 r6:8706ec00 r5:80611314 r4:00000000
[<80560eac>] (mxc_rnga_probe+0x0/0x164) from [<8025914c>] (platform_drv_probe+0)
[<8025912c>] (platform_drv_probe+0x0/0x24) from [<80257c7c>] (driver_probe_devi)
[<80257bfc>] (driver_probe_device+0x0/0x204) from [<80257e94>] (__driver_attach)
 r9:80581cac r8:0000008e r7:00000000 r6:8706ec3c r5:805ab070
r4:8706ec08
[<80257e00>] (__driver_attach+0x0/0x98) from [<8025642c>] (bus_for_each_dev+0x6)
 r7:00000000 r6:80257e00 r5:87035e98 r4:805ab070
[<802563c4>] (bus_for_each_dev+0x0/0x94) from [<80257adc>] (driver_attach+0x20/)
 r7:00000000 r6:873f2380 r5:805ab338 r4:805ab070
[<80257abc>] (driver_attach+0x0/0x28) from [<80256d50>] (bus_add_driver+0x18c/0)
[<80256bc4>] (bus_add_driver+0x0/0x268) from [<802584c4>] (driver_register+0x80)
[<80258444>] (driver_register+0x0/0x134) from [<802594f4>] (platform_driver_reg)
 r7:00000000 r6:805c2e00 r5:00000007 r4:805ab05c
[<802594a8>] (platform_driver_register+0x0/0x60) from [<80259528>] (platform_dr)
[<80259508>] (platform_driver_probe+0x0/0xa4) from [<80560ea0>] (mod_init+0x18/)
 r7:00000000 r6:805c2e00 r5:00000007 r4:87034000
[<80560e88>] (mod_init+0x0/0x24) from [<800086b4>] (do_one_initcall+0x40/0x194)
[<80008674>] (do_one_initcall+0x0/0x194) from [<8053d3f4>] (kernel_init+0xfc/0x)
[<8053d2f8>] (kernel_init+0x0/0x1cc) from [<80027190>] (do_exit+0x0/0x7ec)
---[ end trace 4198eed02050f461 ]---

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>