Remove exit call and mayfail parameter from physmap_common()

The only call path where exit was reached was from physmap functions.

Callers of physmap() et al. which were not prepared to handle
ERROR_PTR return values have been adjusted.
physmap_try_ro() has been renamed to physmap_ro() and physmap_common()
slightly refactored due to the now removed *FAIL parameters.

Corresponding to flashrom svn r1745.

Signed-off-by: Niklas Söderlund <niso@kth.se>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/sb600spi.c b/sb600spi.c
index febeabb..8f93d65 100644
--- a/sb600spi.c
+++ b/sb600spi.c
@@ -353,7 +353,7 @@
 	/* Physical memory has to be mapped at page (4k) boundaries. */
 	sb600_spibar = rphysmap("SB600 SPI registers", tmp & 0xfffff000, 0x1000);
 	if (sb600_spibar == ERROR_PTR)
-		return 1;
+		return ERROR_FATAL;
 
 	/* The low bits of the SPI base address are used as offset into
 	 * the mapped page.