tests/lib/cmsis_dsp: matrix: Limit f16 tc execution on ram => 144

binary_f16 and binary_f16.fpu test cases fail when target
SRAM size is below 140k.
Update test case requirements to set min_ram to 144.

Additionally, remove the platform_exclude hich is now useless
(frdm_kw41z ram is 128k).

Fixes #38826

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>