acpigen_write_package: Return pointer to package element counter

Have acpigen_write_package() return a pointer to the package element
counter so it can be used for dynamic package generation where needed.

Change-Id: Id7f6dd03511069211ba3ee3eb29a6ca1742de847
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/15536
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/x86/acpigen.c

@@ -87,12 +87,15 @@ void acpigen_emit_dword(unsigned int data)
 	acpigen_emit_byte((data >> 24) & 0xff);
 }
 
-void acpigen_write_package(int nr_el)
+char *acpigen_write_package(int nr_el)
 {
+	char *p;
 	/* package op */
 	acpigen_emit_byte(0x12);
 	acpigen_write_len_f();
+	p = acpigen_get_current();
 	acpigen_emit_byte(nr_el);
+	return p;
 }
 
 void acpigen_write_byte(unsigned int data)

src/arch/x86/include/arch/acpigen.h

@@ -38,7 +38,7 @@ void acpigen_write_len_f(void);
 void acpigen_pop_len(void);
 void acpigen_set_current(char *curr);
 char *acpigen_get_current(void);
-void acpigen_write_package(int nr_el);
+char *acpigen_write_package(int nr_el);
 void acpigen_write_zero(void);
 void acpigen_write_one(void);
 void acpigen_write_ones(void);