fbdev: xilinxfb: Use devm_platform_get_and_ioremap_resource()

According to commit 890cc39a ("drivers: provide
devm_platform_get_and_ioremap_resource()"), convert
platform_get_resource(), devm_ioremap_resource() to a single
call to devm_platform_get_and_ioremap_resource(), as this is exactly
what this function does.

Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Helge Deller <deller@gmx.de>