Update CHANGELOG.md for 3.2.0
Update CHANGELOG.md for 3.2.0

Tested-by: Victor Chong <4aabb03bd6dd29c44a49684d87b08ac07e10b492@linaro.org> (hikey aosp)
Tested-by: Igor Opaniuk <ca782e5848fbe7ab0a250faa8ae33b643dd89a09@linaro.org> (poplar)
Tested-by: Igor Opaniuk <ca782e5848fbe7ab0a250faa8ae33b643dd89a09@linaro.org> (rpi3)
Tested-by: Joakim Bech <741f90e2a7f4d9afbad8bd50be20560f4cf38962@linaro.org> (RPi3)
Tested-by: Volodymyr Babchuk <3532d338bb205d79c837de6017433dbed71bb432@epam.com> (RCAR M3)
Tested-by: Joseph Chen <80c6ec8323b5b397c988e3ebe83c48154c3f18db@rock-chips.com> (RK322X)
Tested-by: Kevin Peng <7cba9ad118f8345427678affdec63c06c7f3b30d@marvell.com> (Armada 7K, 8K, 3700)
Tested-by: Sahil Malhotra <bc8c689da66bcf78557149af9d21aafe87699754@nxp.com> (NXP - LS1046A-RDB)
Tested-by: Jens Wiklander <7706914404370d7502c27a0eff493dcf491feb51@linaro.org> (Juno)
Tested-by: Etienne Carriere <f21bc5b8f3ea1962eb45af359f1abea6578cab94@linaro.org> (stm32mp1, GP)
Tested-by: Etienne Carriere <f21bc5b8f3ea1962eb45af359f1abea6578cab94@linaro.org> (b2120/b2260, GP)
Tested-by: Jens Wiklander <7706914404370d7502c27a0eff493dcf491feb51@linaro.org> (FVP)
Tested-by: Jerome Forissier <ced78d268b4c9a0a20a59a9feeebd2ad90da03d3@linaro.org> (HiKey960, GP)
Tested-by: Andrew F. Davis <a6dfde0ec5c5124d26ab0cb4f9ab9a758dee1d6f@ti.com> (TI platforms)
Signed-off-by: Jerome Forissier <ced78d268b4c9a0a20a59a9feeebd2ad90da03d3@linaro.org>

pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os