Endian conversion: move to platform.h and platform/endian*.c

Starting to move the platform dependent code to platform/ and provide
the abstraction through the platform.h header.

Change-Id: I35640282d451960f2a329ae24339ec05dbae6d30
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/62899
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72316
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/meson.build b/meson.build
index e68f8a4..2ccb012 100644
--- a/meson.build
+++ b/meson.build
@@ -133,11 +133,11 @@
 endif
 
 if host_machine.endian() == 'little'
-  srcs += 'hwaccess_endian_little.c'
+  srcs += 'platform/endian_little.c'
   add_project_arguments('-D__FLASHROM_LITTLE_ENDIAN__=1', language : 'c')
 endif
 if host_machine.endian() == 'big'
-  srcs += 'hwaccess_endian_big.c'
+  srcs += 'platform/endian_big.c'
   add_project_arguments('-D__FLASHROM_BIG_ENDIAN__=1', language : 'c')
 endif