ddr: altera: Clean up run_mem_calibrate()

ddr: altera: Clean up run_mem_calibrate()

Clean the function up slightly by using clrsetbits_le32() to flip
bits in registers instead of cryptic bitmasks. Zap condition checking
for PHY_DEBUG_IN_DEBUG_MODE flag, which is never set. Split the
calibration report into separate debug_mem_calibrate() function.

Signed-off-by: Marek Vasut <marex@denx.de>