meson: remove if conditionals for meson versions less than meson_version

The minimum version is too high to allow these checks to ever be false.
We can delete else branches as dead code and remove "if true"
constants.

Fixes:
```
meson.build:170: WARNING: Conditional on version '>= 0.55.0' always evaluates to true
meson.build:232: WARNING: Conditional on version '>= 0.55.0' always evaluates to true
```

Signed-off-by: Eli Schwartz <eschwartz@gentoo.org>

meson.build

@@ -167,11 +167,7 @@ if not (host_machine.system() == 'windows' and get_option('debug'))
  test_ldflags += '-Wl,--dynamicbase'
 endif
 foreach ldflag : test_ldflags
-  if meson.version().version_compare('>= 0.55.0')
   has_arg = cc.has_link_argument(ldflag)
-  else
-    has_arg = cc.has_argument(ldflag)
-  endif
 
   if has_arg and cc.links('int main (void) { return 0; }', args: ldflag)
     global_ldflags += ldflag
@@ -229,7 +225,6 @@ if cc.get_id() != 'msvc'
   meson.add_install_script('meson_post_install.py')
 endif
 
-if meson.version().version_compare('>= 0.55.0')
 summary({
   'prefix': get_option('prefix'),
   'bindir': get_option('bindir'),
@@ -254,4 +249,3 @@ if meson.version().version_compare('>= 0.55.0')
   'Sysinfo': get_option('with-sysinfo'),
   'DCC Checksum': get_option('with-checksum'),
 }, section: 'Plugins')
-endif