package/criu: disable mips

mips raises the following build failure since the addition of the
package in commit 3e4b479f:

compel/arch/mips/plugins/std/memcpy.S:7: Error: opcode not supported on this processor: mips32 (mips32) `dadd $2,$0,$4'
compel/arch/mips/plugins/std/memcpy.S:8: Error: opcode not supported on this processor: mips32 (mips32) `daddiu $13,$0,0'

Indeed, dadd and daddiu are specific to mips64

Building on mips64 doesn't work either as it raises the following build
failure:

/tmp/ccArXSfi.s:305: Error: opcode not supported on this processor: mips64 (mips64) `rdhwr $2,$29'

Fixes:
 - http://autobuild.buildroot.org/results/b0341d0654e66bdac2c91d5949be3810a961d9da
 - http://autobuild.buildroot.org/results/b7b8860476de04980bd8c7241d3dd5a01a0251c8



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>