mtd: spi: renesas: Add 4 bytes address mode support

This patch adds 4-byte address mode support. Because traditional access
based on FIFO/shift register, it's complex to specify information like
opcode, address length, dummy bytes etc to flash. Replace the traditional
access by spi-mem layer which is essential to make 4-byte address mode
support possible.

Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Cong Dang <cong.dang.xn@renesas.com>
Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>