cmake: remove extraneous newlines in build output

Using `west build --board=stm32f769i_disco --pristine=always
samples/subsys/shell/fs/` as an example:

Before:

-- west build: building application
[1/205] Preparing syscall dependency handling

[2/205] Generating include/generated/version.h
-- Zephyr version: 3.4.0 ($ZEPHYR_HOME), build:
zephyr-v3.4.0-9-gec9b30d354ec
[195/205] Linking C executable zephyr/zephyr_pre0.elf

[199/205] Linking C executable zephyr/zephyr_pre1.elf

[205/205] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:       94040 B         2 MB      4.48%
             RAM:       39528 B       384 KB     10.05%
            QSPI:          0 GB       256 MB      0.00%
            DTCM:          0 GB       128 KB      0.00%
          SDRAM1:          0 GB        16 MB      0.00%
        IDT_LIST:          0 GB         2 KB      0.00%

After:

-- west build: building application
[1/205] Preparing syscall dependency handling

[2/205] Generating include/generated/version.h
-- Zephyr version: 3.4.0 ($ZEPHYR_HOME), build:
zephyr-v3.4.0-9-gec9b30d354ec
[205/205] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
           FLASH:       94040 B         2 MB      4.48%
             RAM:       39528 B       384 KB     10.05%
            QSPI:          0 GB       256 MB      0.00%
            DTCM:          0 GB       128 KB      0.00%
          SDRAM1:          0 GB        16 MB      0.00%
        IDT_LIST:          0 GB         2 KB      0.00%

Signed-off-by: Armin Brauns <armin.brauns@embedded-solutions.at>