stm32mp1: remove USB and UART flags in BSEC services

The STM32MP_USB_PROGRAMMER and STM32MP_UART_PROGRAMMER flags are no more
used when compiling BL32.
The services STM32_SMC_READ_ALL and STM32_SMC_WRITE_ALL should then be
always present in the code. They can only be used when booting from serial
device, so a dedicated check is added.
This adds 1.6kB of code.

Change-Id: Ib6ac227a0b451d26b454fef42310665fada90a34
Signed-off-by: Yann Gautier <yann.gautier@st.com>
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/188321


Reviewed-by: CITOOLS <smet-aci-reviews@lists.codex.cro.st.com>
Reviewed-by: Lionel DEBIEVE <lionel.debieve@st.com>