[dif_alert_handler] Use auto-generated Hjson file

The alert_handler is an IP template which is instantiated with a
top_earlgrey-specific configuration. The C header file must be generated
from the templated Hjson file, not the example Hjson file which happens
to be in the tree as well, but doesn't contain the right configuration.

Fixes #5778

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/meson.build b/meson.build
index 80d5d10..52acf77 100644
--- a/meson.build
+++ b/meson.build
@@ -207,7 +207,7 @@
 # TODO: Considering moving these into hw/ip directories.
 TOPNAME='top_earlgrey'
 hw_ip_aes_reg_h = gen_hw_hdr.process('hw/ip/aes/data/aes.hjson')
-hw_ip_alert_handler_reg_h = gen_hw_hdr.process('hw/ip/alert_handler/data/alert_handler.hjson')
+hw_ip_alert_handler_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/alert_handler/data/autogen/alert_handler.hjson')
 hw_ip_aon_timer_reg_h = gen_hw_hdr.process('hw/ip/aon_timer/data/aon_timer.hjson')
 hw_ip_clkmgr_reg_h = gen_hw_hdr.process('hw/' + TOPNAME + '/ip/clkmgr/data/autogen/clkmgr.hjson')
 hw_ip_entropy_reg_h = gen_hw_hdr.process('hw/ip/entropy_src/data/entropy_src.hjson')