meson: make build system happy by replacing deprecated feature

ExternalProgram.path() is deprecated since 0.55, use
ExternalProgram.full_path() instead.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>

etnaviv/meson.build

@@ -61,6 +61,6 @@ test(
   args : [
     '--lib', libdrm_etnaviv,
     '--symbols-file', files('etnaviv-symbols.txt'),
-    '--nm', prog_nm.path(),
+    '--nm', prog_nm.full_path(),
   ],
 )

freedreno/meson.build

@@ -77,6 +77,6 @@ test(
   args : [
     '--lib', libdrm_freedreno,
     '--symbols-file', files('freedreno-symbols.txt'),
-    '--nm', prog_nm.path(),
+    '--nm', prog_nm.full_path(),
   ],
 )