ARM: 9445/1: clkdev: Mark some functions with __printf() attribute

Some of the functions are using printf() type of format, and
compiler is not happy about them as is:

clkdev.c:185:17: error: function ‘vclkdev_alloc’ might be a candidate for  gnu_printf’ format attribute [-Werror=suggest-attribute=format]
clkdev.c:224:9: error: function ‘vclkdev_create’ might be a candidate for  gnu_printf’ format attribute [-Werror=suggest-attribute=format]
clkdev.c:314:9: error: function ‘__clk_register_clkdev’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]

Fix the compilation errors by adding __printf() attributes.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>