[ Upstream commit 815d835b7ba46685c316b000013367dacb2b461b ]

Using over-sampling ratio, lpuart can accept baud rate upto uartclk / 4.
Signed-off-by: NTomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>