Add musl/src/misc/getauxval.c to rules.mk

In order to use getauxval, add musl/src/misc/getauxval.c
to rules.mk.

Bug: 149518090
Change-Id: I892aa58a4d768b82a92013672a214bddbd03f95c
diff --git a/lib/libc-trusty/rules.mk b/lib/libc-trusty/rules.mk
index 70718b7..fbaff60 100644
--- a/lib/libc-trusty/rules.mk
+++ b/lib/libc-trusty/rules.mk
@@ -167,6 +167,7 @@
 	$(MUSL_DIR)/src/exit/atexit.c \
 	$(MUSL_DIR)/src/exit/exit.c \
 	$(MUSL_DIR)/src/exit/_Exit.c \
+	$(MUSL_DIR)/src/misc/getauxval.c \
 	$(MUSL_DIR)/src/multibyte/btowc.c \
 	$(MUSL_DIR)/src/multibyte/c16rtomb.c \
 	$(MUSL_DIR)/src/multibyte/c32rtomb.c \