refactor(msm8916): separate common platform setup code

In preparation of adding BL32 support for the msm8916 platform
(AArch32/SP_MIN and TSP), separate the common platform setup code into
shared msm8916_setup.c and msm8916_config.c files which can be called
from both BL31 and BL32.

msm8916_setup.c contains the relevant shared code for BL31/SP_MIN/TSP,
while msm8916_config.c is cold boot configuration code that is only
relevant for BL31 and SP_MIN (but not TSP).

No functional change.

Change-Id: I055522d5ad8c03dfb8e09236dc47dd383a480e95
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
diff --git a/plat/qti/msm8916/msm8916_gicv2.h b/plat/qti/msm8916/msm8916_gicv2.h
index 99db0d3..919e294 100644
--- a/plat/qti/msm8916/msm8916_gicv2.h
+++ b/plat/qti/msm8916/msm8916_gicv2.h
@@ -8,5 +8,6 @@
 #define MSM8916_GICV2_H
 
 void msm8916_gicv2_init(void);
+void msm8916_gicv2_configure(void);
 
 #endif /* MSM8916_GICV2_H */