am335x_evm: Rework board_is_foo() checks

We rework the various board_is_foo() checks to take a pointer to
struct am335x_baseboard_id rather than using a local copy in board.c.
This allows us to make use of the same checks in mux.c as well as fixing
problems when this code could be running from read-only memory.

Reviewed-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/board/ti/am335x/board.h b/board/ti/am335x/board.h
index 9fea1f1..bc700d5 100644
--- a/board/ti/am335x/board.h
+++ b/board/ti/am335x/board.h
@@ -29,6 +29,37 @@
 	char mac_addr[HDR_NO_OF_MAC_ADDR][HDR_ETH_ALEN];
 };
 
+static inline int board_is_bone(struct am335x_baseboard_id *header)
+{
+	return !strncmp(header->name, "A335BONE", HDR_NAME_LEN);
+}
+
+static inline int board_is_bone_lt(struct am335x_baseboard_id *header)
+{
+	return !strncmp(header->name, "A335BNLT", HDR_NAME_LEN);
+}
+
+static inline int board_is_evm_sk(struct am335x_baseboard_id *header)
+{
+	return !strncmp("A335X_SK", header->name, HDR_NAME_LEN);
+}
+
+static inline int board_is_idk(struct am335x_baseboard_id *header)
+{
+	return !strncmp(header->config, "SKU#02", 6);
+}
+
+static inline int board_is_gp_evm(struct am335x_baseboard_id *header)
+{
+	return !strncmp("A33515BB", header->name, HDR_NAME_LEN);
+}
+
+static inline int board_is_evm_15_or_later(struct am335x_baseboard_id *header)
+{
+	return (board_is_gp_evm(header) &&
+		strncmp("1.5", header->version, 3) <= 0);
+}
+
 /*
  * We have three pin mux functions that must exist.  We must be able to enable
  * uart0, for initial output and i2c0 to read the main EEPROM.  We then have a