arm64: defconfig: Enable TPS6593 PMIC for SK-AM62A

arm64: defconfig: Enable TPS6593 PMIC for SK-AM62A

SK-AM62A-LP uses TPS6593x PMIC (interfaced over I2C) to power the SoC
and various other peripherals on the board [1].

Specifically, the audio codec (TLV320AIC3106) on the board relies on the
PMIC for the DVDD (1.8V) supply.

[1]: https://www.ti.com/lit/zip/sprr459

Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Signed-off-by: Jai Luthra <j-luthra@ti.com>
Link: https://lore.kernel.org/r/20231003-mcasp_am62a-v3-6-2b631ff319ca@ti.com
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>