clk: stm32mp1_calib: fix the limit calibration value

Calibration uses the ARM counter which is 32 bit signed value.
Depending on the clock source, some required timing value cannot
be reached and must be limited to the INT32 max value.

Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Change-Id: If499d33b42c6abebd40b3d7947aa6f709fdeab8e
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/171274


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Yann GAUTIER <yann.gautier@st.com>
Reviewed-by: CIBUILD <smet-aci-builds@lists.codex.cro.st.com>
Reviewed-by: Etienne CARRIERE <etienne.carriere@st.com>