da8xxevm: fix build error

da8xxevm: fix build error

This patch fixes following compile error for da8xx evm

da830evm.c: In function 'board_init':
da830evm.c:222: error: 'DAVINCI_SYSCFG_SUSPSRC_UART2' undeclared (first use in this function)
da830evm.c:222: error: (Each undeclared identifier is reported only once
da830evm.c:222: error: for each function it appears in.)
make[2]: *** [da830evm.o] Error 1

similarly for da850evm.

introduced through commit:
f9fc237f1f07d4e5ff7c9c2da39cabc8d3d7b339

Signed-off-by: Prabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>