Split include/Makefile.am content into subdirs

When someone is modifying a given library there's no need to be looking
at a common file contains tons of lines from different libraries.
Furthermore, this removes the need of "nobase" autofoo prefix, hence
following the usual directive of having one Makefile per directory.

Change-Id: I785891c2f89114bf8303c799094b637d3d25ac71
diff --git a/include/osmocom/gprs/Makefile.am b/include/osmocom/gprs/Makefile.am
new file mode 100644
index 0000000..289be57
--- /dev/null
+++ b/include/osmocom/gprs/Makefile.am
@@ -0,0 +1,17 @@
+SUBDIRS = protocol
+
+osmogprs_HEADERS = \
+	frame_relay.h \
+	bssgp_bvc_fsm.h \
+	gprs_bssgp.h \
+	gprs_bssgp2.h \
+	gprs_bssgp_bss.h \
+	gprs_bssgp_rim.h \
+	gprs_msgb.h \
+	gprs_ns.h \
+	gprs_ns_frgre.h \
+	gprs_ns2.h \
+	gprs_rlc.h \
+	$(NULL)
+
+osmogprsdir = $(includedir)/osmocom/gprs
diff --git a/include/osmocom/gprs/protocol/Makefile.am b/include/osmocom/gprs/protocol/Makefile.am
new file mode 100644
index 0000000..e69527d
--- /dev/null
+++ b/include/osmocom/gprs/protocol/Makefile.am
@@ -0,0 +1,8 @@
+osmogprsproto_HEADERS = \
+	gsm_04_60.h \
+	gsm_08_16.h \
+	gsm_08_18.h \
+	gsm_24_301.h \
+	$(NULL)
+
+osmogprsprotodir = $(includedir)/osmocom/gprs/protocol