code_relocation: fix ruff SUM401 warning

The ruff python linter produces a SIM401 warning when a dictionary is
accessed using if-statements to check for key presence. In this case, the
dict.get() method could be used instead.

For example:

    value = foo["bar"] if "bar" in foo else 0

...can be replaced with:

    value = foo.get("bar", 0)

This patch corrects the single instance of this issue in the script.

Signed-off-by: Joel Holdsworth <jholdsworth@nvidia.com>

.ruff-excludes.toml

@@ -234,7 +234,6 @@
 ]
 "./scripts/build/gen_relocate_app.py" = [
     "E101",     # https://docs.astral.sh/ruff/rules/mixed-spaces-and-tabs
-    "SIM401",   # https://docs.astral.sh/ruff/rules/if-else-block-instead-of-dict-get
     "UP006",    # https://docs.astral.sh/ruff/rules/non-pep585-annotation
     "UP035",    # https://docs.astral.sh/ruff/rules/deprecated-import
     "UP037",    # https://docs.astral.sh/ruff/rules/quoted-annotation

scripts/build/gen_relocate_app.py

@@ -333,7 +333,7 @@ def print_linker_sections(list_sections: 'list[OutputSection]'):
 
 
 def add_phdr(memory_type, phdrs):
-    return f'{memory_type} {phdrs[memory_type] if memory_type in phdrs else ""}'
+    return f'{memory_type} {phdrs.get(memory_type, "")}'
 
 
 def string_create_helper(