tests: drivers: memc: ram: build error on hifive_unmatched

[mars-low]

Describe the bug

Test tests/drivers/memc/ram fails to build for hifive_unmatched platform.

It is a regression caused by 569a4ab.

Regression

• This is a regression.

Steps to reproduce

west build -p -b hifive_unmatched/fu740/s7 tests/drivers/memc/ram -T drivers.memc

Relevant log output

/zephyrproject/zephyr/tests/drivers/memc/ram/src/main.c: In function 'test_ram_test_ram0':
/zephyrproject/zephyr/tests/drivers/memc/ram/src/main.c:74:31: error: 'RAM_SIZE_SRAM' undeclared (first use in this function); did you mean 'BUF_SIZE_SRAM'?
   74 |         test_ram_rw(buf_ram0, RAM_SIZE_SRAM);
      |                               ^~~~~~~~~~~~~
      |                               BUF_SIZE_SRAM
/zephyrproject/zephyr/tests/drivers/memc/ram/src/main.c:74:31: note: each undeclared identifier is reported only once for each function it appears in

Impact

Annoyance – Minor irritation; no significant impact on usability or functionality.

Environment

• OS: Ubuntu 24.04.3 LTS
• Toolchain: https://github.com/zephyrproject-rtos/sdk-ng/releases/tag/v0.17.4
• SHA: 8b2c75a

Additional Context

No response