defconfig: am335x_gp_evm: enable timer driver model

Enable timer driver model for am335x_gp_evm as omap-timer supports
driver model.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

configs/am335x_gp_evm_defconfig

@@ -16,3 +16,5 @@ CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_ETH=y
 CONFIG_SYS_NS16550=y
 CONFIG_RSA=y
+CONFIG_TIMER=y
+CONFIG_OMAP_TIMER=y