build: switch global_arguments to project_arguments

When 'oem-ibm' is enabled there are compile flags that
need to be applied across all files in this project.  To
do that, 'add_project_arguments' should be used and not
'add_global_arguments' because:

    1. These compile flags should only affect this project.
    2. Meson subprojects may not update global arguments.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I360b6e03d37d6dfeab0085253992a443543e94a6
diff --git a/meson.build b/meson.build
index 2e32367..db22dc0 100644
--- a/meson.build
+++ b/meson.build
@@ -41,8 +41,8 @@
   conf_data.set_quoted('LID_ALTERNATE_PATCH_DIR', '/usr/local/share/hostfw/alternate')
   conf_data.set_quoted('LID_STAGING_DIR', '/var/lib/phosphor-software-manager/hostfw/staging')
   conf_data.set('DMA_MAXSIZE', get_option('oem-ibm-dma-maxsize'))
-  add_global_arguments('-DOEM_IBM', language : 'c')
-  add_global_arguments('-DOEM_IBM', language : 'cpp')
+  add_project_arguments('-DOEM_IBM', language : 'c')
+  add_project_arguments('-DOEM_IBM', language : 'cpp')
 endif
 configure_file(output: 'config.h',
   configuration: conf_data