linker: Missing align __itcm_load_start / __dtcm_data_load_start linker symbols

[nandojve]

Describe the bug
The #37938 not update RISCV LD script with __itcm_load_start / __dtcm_data_load_start linker symbols. Because of that, it is not possible to build Zephyr RISC-V with ITCM/DTCM due to following error:

kernel/xip.c:28: undefined reference to `__itcm_load_start'
kernel/xip.c:43: undefined reference to `__dtcm_data_load_start'

The #37938 is current present in v2.7.0-rc1.

Expected behavior
Fix name to allow build using ITCM/DTCM at RISC-V architecture.

Impact
showstopper

Environment (please complete the following information):

• OS: Linux
• Zephyr SDK 0.13.1
• v2.7.0-rc5