ARM: 9331/1: ARM/dma-mapping: replace kzalloc() and vzalloc() with kvzalloc()

using kvzalloc() simplifies the code by avoiding the
use of different memory allocation functions for different
situations, making the code more uniform and readable.

Signed-off-by: Chen Haonan <chen.haonan2@zte.com.cn>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>