drivers/mtd: fix NULL pointer dereference in partition lock/unlock

Some mtd device does not support lock and unlock functions. Adding this check
avoids crashing when mtd_part_lock/unlock are called for such devices.

Signed-off-by: Zahari Doychev <zahari.doychev@linux.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
pci: pci_alloc_bus(): use xzalloc() instead of kzalloc()

Also drop redundant xzalloc() result check
as xzalloc() does not return in case of memory allocation error.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Documentation: add uemd mb7707 barebox mini-howto

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
barebox: common: added new filetypes

- Added omap CH image header recognition
  * filetype_ch_image
  * filetype_ch_image_be

Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
PCM051: Update RAM timings

Updated timings for new MT41J256M16HA15EIT RAM.
Timings are backward compatible to the MT41J256M8HX15E RAMs

Signed-off-by: Teresa Gámez <t.gamez@phytec.de>
Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>