build: Remove GCC ARM warning workaround (originally added in 193d1942)

The workaround was initially added to silence warnings on GCC < 6.4 for ARM
platforms due to a compiler bug (gcc.gnu.org/bugzilla/show_bug.cgi?id=77728).
Since our codebase now requires modern GCC versions for coroutine support,
and the bug was fixed in GCC 6.4+, this workaround is no longer needed.

Refs 193d1942f2

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#21308

configure.py

@@ -1538,8 +1538,6 @@ def get_warning_options(cxx):
         '-Wno-unsupported-friend',
         '-Wno-missing-field-initializers',
         '-Wno-deprecated-copy',
-        # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77728
-        '-Wno-psabi',
         '-Wno-enum-constexpr-conversion',
     ]