board: ti: am57xx: Fix detection of board version

board_is*("rev", board_ti_get_rev()) uses strncmp() for
revison detection and assumes it is success if return value
is <= 0. This will fail in case of multiple versions, as
revb will be true for board_is_*revb() and board_is_*reva().
Fix it by looking for exact match of the string.
Signed-off-by: NLokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: NTom Rini <trini@konsulko.com>

board/ti/am57xx/board.c

@@ -36,11 +36,11 @@
 
 #define board_is_x15()		board_ti_is("BBRDX15_")
 #define board_is_x15_revb1()	(board_ti_is("BBRDX15_") && \
-				 (strncmp("B.10", board_ti_get_rev(), 3) <= 0))
+				 !strncmp("B.10", board_ti_get_rev(), 3))
 #define board_is_am572x_evm()	board_ti_is("AM572PM_")
 #define board_is_am572x_evm_reva3()	\
 				(board_ti_is("AM572PM_") && \
-				 (strncmp("A.30", board_ti_get_rev(), 3) <= 0))
+				 !strncmp("A.30", board_ti_get_rev(), 3))
 #define board_is_am572x_idk()	board_ti_is("AM572IDK")
 #define board_is_am571x_idk()	board_ti_is("AM571IDK")