ramdisk: switch from initrd (ext4 based) to initramfs (cpio.gz based) format

ramdisk: switch from initrd (ext4 based) to initramfs (cpio.gz based) format

Initrd-style booting is deprecated since Linux kernel commit 9acc17baf1fd
("initrd: mark initrd support as deprecated") included in v5.9 release.

Since commit ff26956875c2 ("brd: remove support for BLKFLSBUF") included
in Linux kernel v4.10 it is no longer possible to free the memory
occupied by the initrd.

Switch Tizen ramdisk images to initramfs format (cpio.gz based) to comply
with the new approach of starting Linux based systems.

During build arm64 on QB, ramdisk-recovery is failed because of no space
issue.
- It's a strange issue, so increase the ramdisk-recovery size from
32MB to 64MB.

Change-Id: I67ab60d95b751958f7a42f088047b8f289c58bc5
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>