Fix a potential issue in mpc52xx uart driver
Fix a potential issue in mpc52xx uart driver

mpc52xx_uart_int and __uart_put_char both try to acquire the
port->lock. Therefore the function sequence of:

mpc52xx_uart_int--> ...-->flush_to_ldisc-->...-->__uart_put_char

can potentially trigger a deadlock. To avoid this deadlock a fix
similar to that found in the 8250.c serial driver is applied. The
deadlock is avoided by releasing the lock before pushing a buffer
and reacquiring it when completed.

Signed-off-by: Andrew Liu <2da6379118d98182518033360c0f535bdfa74ea8@windriver.com>
Signed-off-by: Grant Likely <9069e6f5a2b566e2674a0ba1e2bf39c12c195fad@secretlab.ca>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas