selftests: net: fix rps_default_mask with >32 CPUs

selftests: net: fix rps_default_mask with >32 CPUs

[ Upstream commit 0719b5338a0cbe80d1637a5fb03d8141b5bfc7a1 ]

If there is more than 32 cpus the bitmask will start to contain
commas, leading to:

./rps_default_mask.sh: line 36: [: 00000000,00000000: integer expression expected

Remove the commas, bash doesn't interpret leading zeroes as oct
so that should be good enough. Switch to bash, Simon reports that
not all shells support this type of substitution.

Fixes: c12e0d5f267d ("self-tests: introduce self-tests for RPS default mask")
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240122195815.638997-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>