board: ti: am335x: Enable eCAP0 PWM and LCD pin muxing

board: ti: am335x: Enable eCAP0 PWM and LCD pin muxing

On AM335x EVM[1],
1. pin AM335X_ECAP0_IN_PWM0_OUT is used to enable the
backlight. ECAP0 can be configured in single channel PWM mode.
If CONFIG_PWM_TI_ECAP is enabled, perform eCAP0 pin muxing.

2. Pins LCD_DATA0 - LCD_DATA15, gpmc_ad8 - gpmc_ad15 and
lcd_vsync, lcd_sync, lcd_ac_bias_en, lcd_pclk are used for driving LCD.
If CONFIG_AM335X_LCD is enabled, perform the LCD pin muxing.

This is required to enable splash screen support on AM335x EVM.
[1] AM335x EVM - https://www.ti.com/tool/TMDXEVM3358

Signed-off-by: Sukrut Bellary <sbellary@baylibre.com>