kernel.mk: set KERNEL_OUT properly

It was hardcoded to $(ANDROID_BUILD_TOP)/$(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ
which wouldn't exist if OUT_DIR_COMMON_BASE was set to use another dir
(e.g. ramdisk)

Fix it so that it now points to $(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ
if OUT_DIR is not out

Change-Id: I1bf767d86548e41270d9cbb8f0c00512708501c5
envsetup: set OUT_DIR to an absolute path always

OUT_DIR was set to $(TOPDIR)out previously,
but $(TOPDIR) was null, so it was a relative path.
This broke releasetools, inline kernel building, etc
since they require absolute paths.
Fix it so that it is set to $(shell readlink -f .)/out
if $(TOPDIR) is null.

Also remove hacks which checked if (OUT_DIR) was out
and changed it to $(ANDROID_BUILD_TOP)/out to workaround
the aforementioned problem.

Change-Id: I459a3b1325a1bbea0565cd73f6acf160d4ed9b39
qcom_utils: Only define QCOM_BOARD_PLATFORMS if compiling kernel inline

	* If using prebuilt kernel KERNEL_OBJ/usr will not exist, thus
	  build will complain of dir missing during module compilation

	** Requires TARGET_USE_PREBUILT_KERNEL := true in BoardConfig for now

Signed-off-by: bmc08gt <bmc08gt.teamb00sted@gmail.com>
Change-Id: Iecd8c97e89504c60d2f01926318468ac7eb396f9