ARM: tegra: Enable UART-E for T20 and T30

T20 and T30 have 5 UARTs, while T114+ have only 4. Fix this by
adding missing UARTE Kconfig for T20/T30.

Signed-off-by: Jonas Schwöbel <jonasschwoebel@yahoo.de>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>