arm64: dts: ti: k3-am62a7-sk: fix pinmux for main_uart1

arm64: dts: ti: k3-am62a7-sk: fix pinmux for main_uart1

main_uart1 reserved for TIFS firmware traces is routed to the
onboard FT4232 via a FET switch which is connected to pin A21 and
B21 of the SoC and not E17 and C17. Fix it.

Fixes: cf39ff15cc01a ("arm64: dts: ti: k3-am62a7-sk: Describe main_uart1 and wkup_uart")
Cc: stable@vger.kernel.org
Signed-off-by: Hong Guan <hguan@ti.com>
[bb@ti.com: expanded commit message]
Signed-off-by: Bryan Brattlof <bb@ti.com>
Link: https://lore.kernel.org/r/20250707-uart-fixes-v1-1-8164147218b0@ti.com
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>