msm_vidc: Use appropriate device attribute permissions

WARNING: at drivers/base/core.c:579 device_create_file+0x68/0x84()
Attribute transport: read permission without 'show'
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W    3.10.0-rc5-gee3e35b-09314-g74557e3 #641
[<c0014220>] (unwind_backtrace+0x0/0x120) from [<c001212c>] (show_stack+0x10/0x14)
[<c001212c>] (show_stack+0x10/0x14) from [<c00841dc>] (warn_slowpath_common+0x4c/0x68)
[<c00841dc>] (warn_slowpath_common+0x4c/0x68) from [<c0084278>] (warn_slowpath_fmt+0x2c/0x3c)
[<c0084278>] (warn_slowpath_fmt+0x2c/0x3c) from [<c03445c8>] (device_create_file+0x68/0x84)
[<c03445c8>] (device_create_file+0x68/0x84) from [<c0408494>] (android_bind+0x120/0x2a8)
[<c0408494>] (android_bind+0x120/0x2a8) from [<c03f973c>] (composite_bind+0x88/0x18c)
[<c03f973c>] (composite_bind+0x88/0x18c) from [<c03f7a40>] (udc_bind_to_driver+0x54/0xd8)
[<c03f7a40>] (udc_bind_to_driver+0x54/0xd8) from [<c03f7b50>] (usb_gadget_probe_driver+0x8c/0xb8)
[<c03f7b50>] (usb_gadget_probe_driver+0x8c/0xb8) from [<c0421a30>] (android_probe+0x2a4/0x3c0)
[<c0421a30>] (android_probe+0x2a4/0x3c0) from [<c0347ca0>] (platform_drv_probe+0x14/0x18)
[<c0347ca0>] (platform_drv_probe+0x14/0x18) from [<c0346a38>] (driver_probe_device+0x130/0x31c)
[<c0346a38>] (driver_probe_device+0x130/0x31c) from [<c0346c84>] (__driver_attach+0x60/0x84)
[<c0346c84>] (__driver_attach+0x60/0x84) from [<c0345188>] (bus_for_each_dev+0x4c/0x80)
[<c0345188>] (bus_for_each_dev+0x4c/0x80) from [<c03458f4>] (bus_add_driver+0xd4/0x234)
[<c03458f4>] (bus_add_driver+0xd4/0x234) from [<c03471c8>] (driver_register+0xa0/0x138)
[<c03471c8>] (driver_register+0xa0/0x138) from [<c0c31864>] (init+0x24/0x9c)
[<c0c31864>] (init+0x24/0x9c) from [<c0008768>] (do_one_initcall+0xcc/0x180)
[<c0008768>] (do_one_initcall+0xcc/0x180) from [<c0c0029c>] (kernel_init_freeable+0xf4/0x1d0)
[<c0c0029c>] (kernel_init_freeable+0xf4/0x1d0) from [<c071ed18>] (kernel_init+0x8/0xe4)
[<c071ed18>] (kernel_init+0x8/0xe4) from [<c000e1b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>