package/fio: bump version to 2.6, fix musl build

Fixes
http://autobuild.buildroot.net/results/063/0637236b89e3251bbf8b649ff60de0ff19494703/
http://autobuild.buildroot.net/results/2fe/2fefe784fb45368344775c7b6f2eb83e1c0c2104/
and others

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/fio/fio.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-FIO_VERSION = fio-2.1.4
+FIO_VERSION = fio-2.6
 FIO_SITE = git://git.kernel.dk/fio.git
 FIO_LICENSE = GPLv2 + special obligations
 FIO_LICENSE_FILES = LICENSE