platform.h: remove IS_LINUX and IS_MACOSX macros

Replace the remaining uses by the plain macros.
Windows, Linux and MacOS are the only systems with explicit macros.

Only the Windows macro is used in several places. The others can easily
be handled like all other systems.

Change-Id: I23ec8fdcff8202d10ddf5a7520432e5b26b01cd4
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.de>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/58276
Original-Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72245
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed