arm: Generate the kernel.bin file in zImage format.

This allows you to run the kernel using the bootz command, which can be
useful on a board where the manufacturer's u-boot does not support EFI.
The original behavior has not been changed, the zImage binary can still
be run by jumping to the beginning of the binary file.

MFC after:	2 weeks

sys/conf/Makefile.arm

@@ -93,7 +93,7 @@ ${KERNEL_KO}.bin: ${FULLKERNEL}
 	    --output-target=binary ${FULLKERNEL} ${.TARGET}.temp
 	@{ ${NM} ${FULLKERNEL} | \
 	    LC_ALL=C \
-	    ${AWK} -f $S/tools/arm_kernel_boothdr.awk -v hdrtype=v7jump && \
+	    ${AWK} -f $S/tools/arm_kernel_boothdr.awk -v hdrtype=v7bootz && \
 	    cat ${.TARGET}.temp; \
 	 } > ${.TARGET}
 	@rm ${.TARGET}.temp

sys/tools/arm_kernel_boothdr.awk

@@ -38,6 +38,7 @@ BEGIN {
 	# The type of header we're writing is set using -v hdrtype= on
 	# the command line, ensure we got a valid value for it.
 	if (hdrtype != "v7jump" &&
+	    hdrtype != "v7bootz" &&
 	    hdrtype != "v8jump" &&
 	    hdrtype != "v8booti") {
 		print "arm_kernel_boothdr.awk: " \
@@ -107,6 +108,35 @@ function write_v7jump() {
 	write_le32(hexstr_to_num("ea000000") + (gStartOff / 4) - 2)
 }
 
+function write_v7bootz() {
+
+	# We are writing this struct...
+	#
+	# struct BootZ_header {
+	#	uint32_t	code0;		/* Executable code */
+	#	uint32_t	dummy[8];	/* dummy */
+	#	uint32_t	magic;		/* Magic number 0x016f2818*/
+	#	uint32_t	load_offset;	/* Image load offset, LE */
+	#	uint32_t	image_size;	/* Effective Image size, LE */
+	# };
+	#
+	# We write 'b _start' into code0.  The image size is everything from
+	# the start of the loaded image to the offset given by the _end symbol.
+
+	write_v7jump()                        # code0
+	write_le32(0)                         # dummy[0]
+	write_le32(0)                         # dummy[1]
+	write_le32(0)                         # dummy[2]
+	write_le32(0)                         # dummy[3]
+	write_le32(0)                         # dummy[4]
+	write_le32(0)                         # dummy[5]
+	write_le32(0)                         # dummy[6]
+	write_le32(0)                         # dummy[7]
+	write_le32(hexstr_to_num("016f2818")) # magic marker
+	write_le32(0)                         # load_offset (0 -> auto)
+	write_le32(gEndOff)                   # image_size
+}
+
 function write_v8jump() {
 
 	# Write the machine code for "b _start"...
@@ -186,6 +216,8 @@ END {
 
 	if (gHdrType == "v7jump") {
 		write_v7jump()
+	} else if (gHdrType == "v7bootz") {
+		write_v7bootz()
 	} else if (gHdrType == "v8jump") {
 		write_v8jump()
 	} else if (gHdrType == "v8booti") {